For a FOWLR tank, is RO unit a necessity?

[kbkathri]

Currently we are in the process of doing the fishless cycling on our 75 gal. tank, we are about 3 days into it and starting to see some nitrites, about 0.25 ppm. Ammonia at about 1 ppm. Still no significant nitrates, maybe a little more color than the 0. When we filled the tank we used tap water with "Prime".

Since then I have done a lot of reading and have seen where there a lot of people who feel that an RO unit is an absolute must (even read on another site that someone posted they filled the tank with tap water to cycle, and was told to drain the tank and start over). I am still confused as to whether this advice is for all saltwater aquariums or more for reef tanks? We intend on staying as a FOWLR tank only, at least for the foreseeable future.


1. Do I really need an RO unit?
2. If I decide to purchase one, how are most people setting these up? Like you would install in a kitchen, or modifying some other way to get it to deposit directly into my mixing container? I have a 75 gallon tank and figured that I would be using 15 gallons of water every other week.
3. Any specific recommendations on what I should purchase, specific models, type, online site?

Thanks for all the information in advance. This site has been a valuable asset, although I still get confused.

 

[bix]

Can't really answer number 1, I did get one but I also like drinking water I think it would depend how good your town's water is, you can probably get it tested somewhere but not sure where.

I actually installed mine in a closet and didn't hook it up to a tap. Just put a hose with a valve that I can turn off and a whole bunch of extra hose. So I can fill up my tank just by attaching the long hose and running it to where the tank is.

When I'm not filling up the tank I can detach the long hose and turn on the valve to fill up a water bottle or whatever I'm drinking out of. It comes out pretty fast but you get used to it.

It's "unconventional" but it works and I'm single so whatever.

I got a 50 gallon per day unit and it works good enough. I can fill up one of those 18L bottles in about 5-10 min but then it slows down. When I was filling up my display tank I just ran the hose and left it going for about 2 days.

Hope that helps!

 

[Ziggy953]

IMO an RO/DI unit is a must for SW systems. FOWLR or Reef doesn't matter. You want to start with the purist water possible and with a RO/DI unit you are building from a good foundation.

I have had mine hard plumbed into it's own supply line and as recently as tonight I've got it under the sink in my kitchen. I'll take some pics for you and post them when my camera comes home in a little while.

As for what kind to buy, the name on the side doesn't matter much. They are all pretty standard now, I suggest at least a 5 stage unit. Aside from that it doesn't matter much.

 

[kdogg85]

If the tank was fish only(fake decorations), dechlorinated tap would work. since you have rock, it is a must or you will battle bad algae depending on how bad the tap water is, it can't be that great. The rock is where the bacteria(good and bad) comes from. Starve out the food source, starve out the bad algae.

As for buying a unit, ziggy is right, they are all pretty standard. Ebay has them for around $100, bulkreefsupply has them around 1-$200. I have the bulkreefsupply 5 stage plus chloramine kit and it works fine. Takes about 6 hrs to do 40g with 50 psi of water pressure. Whichever one you buy, get one with a tds(total dissolved solids) meter.

A RO only unit should get the water down under 10ppm tds, a RO/DI(de-ionization) unit will get the tds to 0. 0 is the number to shoot for, but I let mine get to around 4ppm and then change the filters.

 

[RLG2182]

I have my RO/DI under my kitchen sink. Real easy to plumb in. Have a shut off at the source to shut off water coming into the unit if I need to change the filter cartridges. Waste water gets flushed down the drain.

For the output pure water line I ran a line of 1/4 tubing (like the tubing you use to hook up a fridge water line or ice maker) all the way to the tank along the baseboard nice & neat. I have a 10 gallon tub under my tank that has a float valve to shut off the water once it's full... VERY IMPORTANT. It's like this one here. All very cheap materials to keep cost down. RO/DI units can vary in price. One similar to this will pay for itself quickly. Just follow directions on how often to change out filter cartridges & DI beeds.

From there, if you want to get fancy, you can hook up an automatic top-off unit that you can make cheap as well. You wire a float switch like this one. You can find them all over ebay for under $10 shipped. I have a small water pump in the 10 gallon tub on a timer to pump water into my sump until it hits my desired level. The timer turns the pump on twice a day for only 5 min. That float switch turns off the pump automatically. (the timer is used for redundancy in case the switch fails for whatever reason).

Let me know if you need pictures/directions on how to do this. With my setup, I never have to pull out a single water jug to manually top-off. Shop smart and the whole thing, including RO/DI, auto top-off, tub, water pump, timer, everything... would be under $175.

 

[kbkathri]

Ok. This is the RO/DI system we purchased. I hope this is ok.

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I can't believe how much we have spent on this 75 gallon tank and still haven't any fish. A free virtual cookie to whoever guesses the closest. We still don't have a protein skimmer or a QT tank.

 

[Floyd R Turbo]

First, don't bother to test NitrAte until your Ammonia and NitrIte are 0. Most NitrAte kits convert NitrAte to NitrIte and then measure, so your NitrAte reading will be way high if you have any NitrIte present.

Second, I would say yes, an RO system is a must, I can't tell you how well using RO/DI water solved algae and Cyano problems in the tanks I work on. I got mine off eBay (purewaterclub, I believe, was the seller), I got a 150 GPD w/dual DI for $114 shipped, then I got a TDS meter to test the output water on occasion. I just connected mine directly to the cold water line after the softener in the basement, and then only turn it on to fill a 44G BRUTE trash can, where I then heat and mix salt a day or two before any PWCs. For your uses, a 50 GPD system and a 20 G trash can would work.

You could also hook up the system for home drinking water use, and get a holding tank so you always have a drinking water supply. However, I will let you know that the TDS of water going into the holding tank will increase as the tank fills, so you don't want to use that for your tank, even after running it through the DI (which will go to fast anyways, and burn out your resin).

This is something I came across, and I confirmed it in discussion with someone working with RO systems for 20 years. I noticed something strange when I was testing my RO water (before the DI - I installed a tee and a tap valve) that when I first started it flowing, the TDS would start at 150-200, and then slowly ramp down to below 20. When your RO membrane is not producing, it allows more time for the concentrated contaminants to cross over the membrane, whereas they would not have enough time during production.

Also what happens when you are filling a pressure tank is that as the pressure tank fills, the backpressure increases and for some reason, this also allows more ions to cross over. It didn't make much sense to me at first, but it's some kind of physics thingamabob that I can't remember at this time. This is really only the case where you have a flow limiter on the discharge line. Those are added to these systems to achieve a better discharge to filtered ratio (1.25:1 for mine, I think). If there is no flow limiter, you end up with something like 20:1 so it's a give and take.

Sorry for the dissertation. I'm bored today.

Oh yeah - don't drink DI water, only the RO water. DI water is really, really bad for you.