Advice for Switching to RO Water

[hansgruber7]

I've been having high ammonia and nitrates in my tanks and I just assumed that I was doing something wrong. I finally decided to test the tap water and discovered that it had higher levels of ammonia and nitrates than my tank water! I assume I need to switch to RO water to solve the problem. I've been trying to research this, but I've been discovering conflicting information. I feel a bit foolish that I had not considered this possibility before, but I'm a relative beginner and wasn't even testing my water for a while because I didn't understand all of this. What do I need to keep in mind as I switch to RO water? My local fish store said I could buy some from there regularly.

1. Do I need to worry about PH, GH, KH? I have a betta tank, a CPD/Kuhli loach tank, and a dwarf shrimp tank.
2. Anything else I need to consider as I switch from tap water to RO water?

 

[ClownLurch]

Amazon and eBay sell RO water converters for varying prices some for under £50.....the way things are going over here lately that’s probably $5 but I digress.
Beware they waste a lot of water. Get it plumbed so that the waste goes into a water butt* if you can........if you’ve got a garden that is. Or even into your swimming pool, we know you’ve all got one of them.
Dont get a salt based water softener as they just add sodium into the problem.


*Whats the betting THAT doesn’t translate properly across the pond?

 

[seangee]

What are the levels in your tap and in your tank? Its unlikely that the nitrate in your tank is lower than in your tap. Ammonia may not be a problem if your tank is cycled or planted, or if chloramine is used in your water supply. I assume you don't have dying fish and if it drops in your tank it means the filter is dealing with it.

Your betta, shrimps and (possibly) CPD need some minerals in the water. I would suggest a GH of between 5 and 7 dGH which wll work for all of your species. What is the GH of your tap water? It may make more sense to dilute your tap water with RO rather than use pure RO. If you provide more info on your tap water we can advise better.

 

[hansgruber7]

The levels in my tap water are about 1ppm for ammonia and a little over 20ppm for nitrates. I have three tanks. My betta tank had a little over 0.5ppm ammonia, while me shrimp and CPD tanks had a little over 0.25ppm for ammonia. On nitrates, my betta tank was actually over 40ppm, while my shrimp and CPD tanks were slightly lower if I remember correctly.

My tanks are established and planted, but I have been having dying fish in recent months. My shrimp tank used to be a shrimp and harlequin rasbora tank. All six of my rasbora died one by one, which I assumed was a disease. I have bought probably 20 total CPDs, and only eight lived to adulthood. My betta has severe fin rot and looks unhealthy. So I think my water quality is a consistent problem that I have not been able to tackle despite regular water changes and maintenance.

I do not have GH tests so I don't know. Would RO water be between 5 and 7 GH or would I need to adjust it? Or mix with tap water?

 

[seangee]

RO water has 0GH. So you would need to add a mineral supplement. As long as your tap water is not very soft you could mix tap water with RO. A 50/50 mix would halve the GH in your tap water.

 

[boshk]

So with a reef tank, the 'ideal' way is to use RODI water, RO part usually filters the tap water to 5 tds, then the DI portion gets it down to 0.

I've been reading that certain fish require different parameters but in general, for freshwater tanks, whats an acceptable TDS if using RO part only?

I currently have a Reef tank setup with RODI, thinking of switching back to planted low tech.
GH-dont have a test kit yet for it
Tap water TDS=120
After RO TDS=6
After DI TDS=0

but as you know, with RO water, theres alot of wastage, I already have a 2nd RO attachment to reduce the wastage, is it possible to further reduce waste water?

 

[seangee]

TDS is not something we typically measure. DI is definitely not needed. GH is the number that matters. There is no direct link between TDS and GH (TDS measures everything in the water). But as a quide my tap water is very hard and has a TDS of over 300. I would expect a TDS of 120 to be fine for all of your stock in which case you can use tap water which won't waste anything. The best way forward would be to test your tapwater for GH. You may also want to test for nitrates. This is just based on my own experience because my tap water has high nitrates (50ppm) so is unsuitable for fish.