powerhead strength?

[martano]

I have a 40b with soft corals and fish. Currently running two 165gph oscillating powerheads. They seem to work, but I have a 800gph on stand by which is a propeller fan type. Would this be better than what I am using?

 

[carey]

I would for sure try the higher gph powerhead, the ones you have are really really small.

 

[Shirtlessbill]

What I was told (and now am a believer in) is to add the sum total gph together then divide by the size if your tank. This "turn over" rate puts you into tiers: 30x: good for FOWLR, 40x: softies and some LPS/SPS, 50x: LPS/SPS.

My tank for example is a 75 gallon with (2) 1400 gph power heads and I just added a small 425 to help with a slow area. So (2800+425)/75=43.

 

[Phranque]

The recommended turnover rates vary with opinion, but shirtlessbill has the right idea..... with two 165's in a 40, that's only 8.25 turnover, which is not enough. Adding the 800 in there with those will give you just over 28x..... not bad for softies. Since this is a fairly large single pump for a 40, you will probably need to play around with it's placement so you optimize it's flow but not be blasting your corals.

 

[martano]

I have found a cheap 582gph propeller style on ebay. I believe that will put me at 34x turnover rate. I have a hammer, torch, monipora, and acropora mushroom. The rest are soft corals. I hope that will be enough water flow because the 800gph moves it pretty well, I have it place at the top of my tank.

 

[Callen]

This is just what i was looking for! Do you count the return pump volume in the turnover rate? I don't see it in the examples above, but surely it contributes to the total turnover?!

 

[martano]

I have about 300gph from my sump, total water is 60g. Display holds 40g sump holds 20g. I have not been counting my return as water movement.

 

[Callen]

BTW I was asking a question not making a statement. . I really don't know the answer! Just seems to me the return is causing some movement. But that could be cancelled out by the outflow.

 

[martano]

I dont count it because the flow is insignificant.

 

[carey]

Depending on the tank the output may be more than insignificant. I have a 1400gph return pump for example. While I dont necessarily count it, I do consider it cause it actually does make my corals sway, even without a powerhead on.

I aim to have the most flow I can without fish struggling or sand blowing around. For me, it kinda works itself out in my head automatically lol. I have 2 1400's in my 90g fowlr for instance with a return of 900gph. That is sufficent for that tank but gives me a good flow pattern. My 125g only has the wp40 running at the moment with the return BUT most of my corals are moving and getting a good flow. I intend on adding a second wp40 to it sometime soon. It all comes down to placement and angles in the end. You also need enough flow so that the sandbed is constantly being swept of matter so you dont have dead spots and stuff doesnt accumulate which can help algae and nitrates mulitiply.

 

[saltcreep1025]

acropora mushroom?

 

[martano]

Ricordia mushroom

 

[Shirtlessbill]

Like most things in this hobby there is not a hard and fast rule but more of a guideline that people have found success with. I personally don't factor in my return pump because I am under the school of thought that I don't want too much flow going through my refugium. I like the idea of giving my filtration enough time to get out what it can as opposed to forcing water through it. Just what I have found success with.

 

[Mcmcoker]

Like most things in this hobby there is not a hard a fast rule but more of a guideline that people have found success with. I personally don't factor in my return pump because I am under the school of though that I don't want too much flow going through my refugium. I like the idea of giving my filtration enough time to get out what it can as opposed to forcing water through it. Just what I have found success with.

Agreed with shirtlessbill, I work in the pool and spa industry and our goal is to achieve the needed turn over rates while flowing water through the filters as slow as possible. The harder or faster you push water through the filter the less it is going to catch. I do however count the flow rate from the return pump towards your total turn over rate even as minimal as it may be because this is water that is being filtered. Your power heads do account for most of your turnover but keep in mind that this is simply water that is bring moved around the tank( not filtered) for you geeks out there, 6 turns equals 98% dilution. In other words it takes 6 turns to almost completely exchange all the water in the tank but this only really applies to water passing through the filter so using the formula above you can calculate how long it would take your filter exchange all the water in your tank if you know the flow rate of your return pump.

 

[mr_X]

This may ring true for floss type filters but not for algae. Algae simply needs to be in contact with water to get everything it needs. Fast or slow flow, it's only going to take what it can use.

As for counting the return pump as DT flow, of course you should count it. If it's contributing to the flow inside the DT, then yes, but only after head loss of course.

 

[Callen]

If the pump doesn't give a gph measure, can you tell from the volts, hz,, watts and other things that are listed on it? I have no idea what my return pump capacity is, but it appears to be doing fine.

This is all I can find on it:

 

[mr_X]

That appears to be a mag18, which is 1800 gph.

 

[Callen]

I assume that contributes a good bit to the flow formula? All I've got going is that and a koralia 1200 power head in a 75 gallon.

Through my personal thread which is on a similar topic of " flow" right now, I've learned that we are just trying to eliminate any dead spots in the tank. Considering this thread, if I wanted to inhabit any type of marine creature, I need to get the turnover rate up there and keep flow over all areas.

Given current equipment, and using the return in the calculation somehow, what is my turnover rate?

To the OP, don't mean to hijack your thread, just hoping this info helps others too since you were already on the topic

 

[Mcmcoker]

Your turn over rate is 40 per hour which is pretty good but you may want to consider getting a 800 gph power head for the opposing side of the tank just to ensure there's no dead zones

 

[mr_X]

I assume that contributes a good bit to the flow formula? All I've got going is that and a koralia 1200 power head in a 75 gallon.

Through my personal thread which is on a similar topic of " flow" right now, I've learned that we are just trying to eliminate any dead spots in the tank. Considering this thread, if I wanted to inhabit any type of marine creature, I need to get the turnover rate up there and keep flow over all areas.

Given current equipment, and using the return in the calculation somehow, what is my turnover rate?

To the OP, don't mean to hijack your thread, just hoping this info helps others too since you were already on the topic

It depends on how much head loss you are experiencing. Is the sump directly underneath? How many 90's and bends does the return line(s) have?
How far upward does the water have to travel?