The Python Challenge

[HooKooDooKu]

I brought up some questions regarding the use of the Python "No Spill" for during PWC over in this thread: http://www.aquariumadvice.com/forums/f12/pwc-question-112877-3.html

As I do not own a Python at this time, I can not attempt to verify my suspicions, and I'd like to see if some Python owners can help determine just how much water a Python uses.

First, a couple of phrases copied from Python's web site:

"Environmentally Responsible! Due to our powerful 7 to 1 suction ratio, cleaning your tank uses about the same amount of water as flushing your toilet"
No Spill Clean & Fill Python Productss

"We recommend only a 5 to 10% water change every other week."
pythonwebpage

So I started running some numbers.

The wikipedia article on flush toilets indicates the following:
"The conventional flush-toilet or gravity-fed toilet uses 13 litres (3.4 US gallons or 2.8 imperial gallons) or more per flush."
Flush toilet - Wikipedia, the free encyclopedia

Next, I make an assumption:

Python does not specify what size tank or how much of a PWC is being done when they claim it uses less water than a toilet flush. Obviously they are not going to base the claim on a large water change of a huge tank. And hopefully, they have enough scruples to not base a claim on some rediculously small tank (like a 2.5 gallon tank).

Based on the price of typical glass fish tanks, it appears that the 10 gallon is THE STANDARD when it comes to fish tanks. After all, a 5 gallon tank cost as much as a 10 gallon, and even the jump to 15 gallon can more than double the price of a 10 gallon. So I believe that Python is going to make their claim based on a standard 10 gallon tank.

I also assume, that since they want the claim to look as good as it can, that they are going to base it on the smallest PWC that they recomend.

The Numbers:
So that suggests that the claim is based on a 5% water change in a 10 gallon tank. That means we are going to use about 3.4 gallons of tap water to change out 0.5 gallons of tank water. Now look at those numbers. If we round the 3.4 gallons for the toilet up to 3.5, there is your magic 7-to-1 number.

So if I am right, then a Python uses 7 gallons of water to empty 1 gallon from your tank.

Now I'll admit I MIGHT be totally off base. I've never used a Python myself, and the claims do not specify tank size, or even the type of toilet being used (after all, there are low-flow toilet standards that call for much closer to 1 gallon per flush).

Well over in that other thread, a couple of Python owners claim I have this 7-to-1 ratio backwards, that it's 1 gallon of tap water for 7 gallons of tank water. I've already pointed out the potential flaw in the thinking of when of these claims on the other page, so I'd like to see a Python owner do a direct measurement and see exactly how the Python fairs.

First, the setup. For the test to be valid, we need a fish tank that is about the same height as the sink being used to run the Python. After all, think typical tank stand height verses typical sink height. So if you have a tank mounted in an unusually high spot, an unusually low spot, or if you are using an outdoor hose bibb or a sink located on a different level of your house as the tank, those don't qualify as a vaild test.

Next, use your Python to empty some of the water from your tank. But don't let the water (tap or tank) go down the drain. If you can, place a 5 gallon bucket under your faucet to catch the water. If you don't, then just plug up the sink and run the Python until the sink almost fills up. The test is likely going to require two people, so that you can already have the Python in the tank ready to start sucking up tank water the momen the faucet is turned on. When the sink is ALMOST full, stop the water. To make the test fair, quickly pull the Python out of the tank (don't want water to siphon back into the tank) and empty all the water out of the Python hose into the sink. Next, measure the amount of water in your sink. An estimate would be fine. One way to do so would be to empty the sink using a quart jar, or a gallon tea pitcher, anything to allow you to measure the amount of water in the sink. Next, use a similar quart jar or gallon pitcher to refill the tank back to the exact level it was before you started.

Finally, report how much water was in the sink verses how much water was replaced in the tank. If I am right, then given the sink had tap water and tank water, there should be an 8-to-1 ratio of sink water to tank refill water.

I will be greatly suprised if someone finds that they used less than one quart of tap water to empty 1 gallon of tank water.

 

[missileman]

The easiest way to do it would be to hook the Python to a garden hose so you can run it at a controlled height and easily get it in your bucket.
My garden hose is frozen right now.

 

[Fishyfanatic]

I think there are way too many variables in this and not enough constants. You'd have to ahve the same water pressure, remove the same amount of water, and the same height of the tank and sink. I would consider the "standard" as being 55 gal but that's just because it seems to be what our lfs sells the most of.

Given my own water changing experiences, I would have to waste 15 gal of water per minute while doing a water change. My water pressure is nowhere near 15 gal per minute.

 

[HooKooDooKu]

I think there are way too many variables in this and not enough constants. ...

I'm not looking to determine EXACT numbers. But I would like to see how much water people are practically using. I'd also like to compare that to the company's claim of 7-to-1. But at the same time, I also want to exclude from examples people that use a downstair faucet for an upstairs tank. In such a situation, the siphon effect becomes enourmous. After all, a 10 foot tall water colum equates to 4psi of pressure. That's a lot of pressure to suck water out of a tank.

Actually, I recently did aquire a Python 25 foot extension hose that was discounted at PetSmart. I purchased that allong with the sink adapter and I've been using it as a siphon and refill (meaning I'm NOT using tap water to create a suction to get water out of the tank).

When I recently stuck the end of the hose out the window and let it drop to the ground and started siphoning all the water out of a 20 gallon tank, with that roughtly 10 foot drop from the window ledge to the ground, I was able to empty the entire 20 gallon tank in less than three minutes. That's faster than water can come out of a kitchen sink faucet (which should be on the order of 5 gallons per minute).

 

[CTD]

I run the faucet for about a couple Min's just to get the water suctioning through the Hose (Garden Hose hooked to a Lee's Drain and Fill) then I shut the faucet off and gravity does the rest of the draining for me (Slower but less waste) since as luck would have it my tank is above the height of the faucet.

I am planning (as a Green Measure) on adding an extra Water Barrel along side of the RO Water Barrel to hold the PWC Water from my tanks and pumping the PWC Water from the Barrel using a Pump and Hose outside to water our Flowerbeds instead of sending it down the Drain as an effort to do my part to become more Eco-Logical.

 

[JasonC]

I wonder if there would be an economical way to filter the PWC water you are saving, and then run it back through an RO/DI unit? In essence, recycling the water for future use?

This would be super interesting to me and I have seen a very noticeable difference in my water bill since setting up a tank... and thats only with a 20Gal... I cant imagine whats going to happen when I finally get around to cleaning and setting up the 55 sitting in my basement... nor can I imagine how you all can afford to keep a 100+ Gal tank running ;P

 

[Fishyfanatic]

You shouldn't be noticing a much of an increase in your water bill. Especially with a 20 gal tank. Lets say you change even 50% once a week, that's only 50 gals that you've used in the first month (including the initial fill up). So a 50% water change every week you're only looking at 40 gals of water a month. Our water/sewer bill runs about $30 a month and that is for 2 people to shower every day, toilet flushes, dish water, ice/drinking water, and cleaning/maintaining a 150, 55, and 29 gal tank.

 

[Roberz00]

Wait a min... you mean to tell me that your supposed to use your faucet water to "pump out" the tank during PWC's when using the Python ??? Oh snap...I have been doing it all wrong then. I lay my hose out into my flower bed and let gravity do its thing, Then I hook the hose back up to the faucet adapter and fill the tank from there. No wasted water on my end. Oh, and this is on my fresh water tank since I use LFS supplied, yes supplied, RO/DI salt mix for the salt tank.

 

[gzeiger]

It actually doesn't matter if the tank is at the same height as the sink, as long as you're emptying into the same sink your water is coming from. Conservation of energy tells you that the siphon effect on the downward journey must be exactly balanced by the reverse effect of pumping the water from the sink uphill, and the reverse will be true for tanks placed lower than the sink.

On the other hand, variations in tapwater pressure between different users would mean very different results for the same Python used in different homes.

 

[JasonC]

You shouldn't be noticing a much of an increase in your water bill. Especially with a 20 gal tank. Lets say you change even 50% once a week, that's only 50 gals that you've used in the first month (including the initial fill up). So a 50% water change every week you're only looking at 40 gals of water a month. Our water/sewer bill runs about $30 a month and that is for 2 people to shower every day, toilet flushes, dish water, ice/drinking water, and cleaning/maintaining a 150, 55, and 29 gal tank.

It was definitely there though... note that I have had several occasions where I had to med the tank and was doing 50% every day for several weeks. Regardless, there was definitely a jump on my water/sewer bills starting with the bill in the month that I set the tank up. I wouldn't have thought it would be so bad either... mind you, in normal months, its not that bad, but esp. these days, I have to watch every penny going out.

 

[HooKooDooKu]

It actually doesn't matter if the tank is at the same height as the sink, as long as you're emptying into the same sink your water is coming from. Conservation of energy tells you that the siphon effect on the downward journey must be exactly balanced by the reverse effect of pumping the water from the sink uphill, and the reverse will be true for tanks placed lower than the sink....

Huh

What are you talking about?


How efficient the Python works (i.e. how much water it consumes) is very much a fuction of the relative height of the water level in your tank and the height of the faucet it is connected to.

The Python performs two complete seperate functions.

The first function is to pump the water out of your tank and dump it down the drain. To accomplish this, the Python utilizes water pressure and water flow to power a water pump that suctions water out of the tank. They actually call that 6" thing connected to the faucet a 'faucet pump'. All of the tap water used to power this pump is wasted as it simply goes down the drain once it has accomplished the task of powering the pump. The efficiency of a pump, regardless of whether is is powered by water, electricity, or something else depends totally on the height differential between the water level of your tank and the 'faucet pump' as this determines how high the pump has to lift water. The higher you have to lift water, the more power is required. And when tap water is your source of power, then the higher you have to lift water, the more tap water you are going to use/waste. If the tank is below the level of the sink, then the pump is supplying all of the energy to lift that water. If the tank is above the level of the sink, then gravity is supplying some of the energy to pump the water out of the tank, and the Python 'faucet pump' just speeds up the process by providing additional suction in addition to what gravity is supplying.

Now as a totally seperate function that doesn't use the 'faucet pump' (except for use as a flow path so you don't have to disconnect/reconnect any pipes) is to refill the tank. In this case, you are just using water pressure to push water back into your tank. The height differentail here doesn't really matter much. The reason is because a faucet is going to be supplying 30 to 50 psi to push the water to the tank. But even if the tank is 10 feet above the sink, the water in the python is going to be pushing back with only 4 psi (a column of water 10 foot high creates a pressure of 4 psi). And when you are filling the tank, no water is wasted because water pressure isn't being used to power any device. The water pressure is simply pushing itself.

 

[cogburn]

i have a well... so i dont have a water bill... just the electricity used to run the well pump and the propane used to heat the water... i think it will be negligable

 

[missileman]

I don't have a sewer so I only have a water bill and my water is $2.50 per 1,000 gallons so it would take an awefull lot of water changes before I see any effect on my water bill.

 

[Sombunya]

You shouldn't be noticing a much of an increase in your water bill. Especially with a 20 gal tank.

I think I'm paying about a third of a cent per gallon for my tap water. Three gallons for less than a penny. I change about 50 gallons twice a week. May take more than that to pump it out. If I use 300 gallons a week to do my water changes then I'm paying less than a dollar to do it.

And my lawn gets watered well too.

 

[kreesdqban]

Idk how much Im paying for water (i dont pay the bill lol), but I siphon the water straight out the window into to the garden and fill her up with the hose. Works for me, no Python needed!

 

[jim692]

So if I am right, then a Python uses 7 gallons of water to empty 1 gallon from your tank.

No, you are mistaken on this point.

First, the setup. For the test to be valid, we need a fish tank that is about the same height as the sink being used to run the Python.

Not really.

So if you have a tank mounted in an unusually high spot, an unusually low spot, or if you are using an outdoor hose bibb or a sink located on a different level of your house as the tank, those don't qualify as a vaild test.

No, the results would be a perfectly valid under those conditions.

I will be greatly suprised if someone finds that they used less than one quart of tap water to empty 1 gallon of tank water.

Me too.

How efficient the Python works (i.e. how much water it consumes) is very much a fuction of the relative height of the water level in your tank and the height of the faucet it is connected to..

No.

The efficiency of a pump, regardless of whether is is powered by water, electricity, or something else depends totally on the height differential between the water level of your tank and the 'faucet pump' as this determines how high the pump has to lift water.

No.

The water pressure is simply pushing itself.

What?


OK, I'll bite. I think this would be fun to see what the 25' Python could do in a real world test. Since I have the right equipment to test this item, why not. Ground rules. The "sink" will be 32" off the floor and the tank will be 50" off the floor to the top of the tank. These should be fairly common measurements. The venturi pump of the Python has a 5/32" orifice on the faucet supply side and a 1/2" orifice on the suction side to the gravel vac. On the water supply line, there will be a pressure transducer and a flow meter. Water will be drawn from the "tank" (55 gallon drum) and also metered. The test will run for as long as possible until the "tank" is empty.

Results:
Water temp -47*F.
static water pressure - 81.4 psi
residual water pressure - 77.9 psi
Run time - 12.00 minutes
water removed from "tank" - 53.37 gallons
water supplied from "faucet" - 27.69 gallons

So, this gives us 4.4475 gpm removed from "tank" and 2.3075 gpm supplied from "faucet". That is almost a 2 to 1 ratio which is not too bad with the variables involved such as hose diameter, hose length, bends & curves, c-factor, elevation difference(ft of head), etc. Like any pump the claimed performance is most likely based on theoretical models or test conditions arranged for maximum benefit. That is probably the case for the 7 to 1 ratio that is advertised.

I still like the Python and will still use it because:
Way less messy than buckets,
It sends the old water down the drain,
It doesn't take up much room,
2 to 1 ratio is still pretty good,
It's fairly quick to use,
It's a nice shade of green. lol.

 

[missileman]

2 parts aquarium water to 1 part tap water?
Sounds about right based on my known unrestricted waterflow rate vs amount of water normally siphoned vs time. I actually calculated closer to 1:1 ratio but that did not factor in the restricted tap water flow which should lower tap water usage.
Same here, I like the Python simply because it makes my job so much easier.
And it does clean gravel better than a standard gravity fed siphon.

 

[HooKooDooKu]

...
OK, I'll bite. I think this would be fun to see what the 25' Python could do in a real world test. Since I have the right equipment to test this item, why not. Ground rules. The "sink" will be 32" off the floor and the tank will be 50" off the floor to the top of the tank. These should be fairly common measurements. The venturi pump of the Python has a 5/32" orifice on the faucet supply side and a 1/2" orifice on the suction side to the gravel vac. On the water supply line, there will be a pressure transducer and a flow meter. Water will be drawn from the "tank" (55 gallon drum) and also metered. The test will run for as long as possible until the "tank" is empty.

Results:
Water temp -47*F.
static water pressure - 81.4 psi
residual water pressure - 77.9 psi
Run time - 12.00 minutes
water removed from "tank" - 53.37 gallons
water supplied from "faucet" - 27.69 gallons

So, this gives us 4.4475 gpm removed from "tank" and 2.3075 gpm supplied from "faucet". That is almost a 2 to 1 ratio which is not too bad with the variables involved such as hose diameter, hose length, bends & curves, c-factor, elevation difference(ft of head), etc. Like any pump the claimed performance is most likely based on theoretical models or test conditions arranged for maximum benefit. That is probably the case for the 7 to 1 ratio that is advertised.
...
[/quote]

Thank you so much for provided a measured practical example.
I had since actually looked at the mathmatical formual regarding the venturi effect and was suprised at how much suction could potentially be created by this type of setup.

One minor question? Where are you measuring the water pressure at over 80 psi. A plumping "standard" is to keep holdhold water pressure below 50psi, installing a pressure regulator if neccessary. As I understand it, many house hold appliances (say a dish washer) are designed for only 50psi. So usually, the only place you get a pressure measurement above 50psi is an outside hose bibb that connects to the water supply before the pressure regulator. (I learned about some of these things installing an irrigation system a few years back).

If you truly have 80+psi at your sink, then your results might not be typical.

 

[asudavew]

I just bought one, and I can't get it to pump squat out of my tank.
It's fifty foot and the sink is 36 inches high.

My tanks are all about 30 at the bottom.

ugh

I have to manually start the siphon and then I drain it outside to the flower garden.(That was my original plan anyway.)

But any idea why the faucet can't start the siphon>?

 

[missileman]

Do you have the bottom piece (valve) unscrewed and pulled down all the way?
Mine sucks so hard it sounds like a vacuum cleaner.