Quote:
Originally Posted by
jayjay5531 http:///t/396386/ro-di-for-fowlr-san-francisco#post_3531711
So I live in San Francisco (Yay Area represent!) and all the tap water here comes from Hetch Hetchy, which has an average TDS of 50 ppm or so (be jealous...lol). Right now I have a 36 gallon FOWLR with a couple of Oscellaris clowns, 1 Banggai cardinal, a cleaner shrimp, lotsss of nassarius snails, a brittle star, some green crabs (what are they called again?) and a sally lightfoot crab. So yeah, only three fish...Probably going to add a few more later.
I'm not exactly clear why RO/DI water is helpful for FOWLRs in the first place... is it just to prevent algae growth?
Regardless, is it a worthy investment to get a RO/DI or RO filtration unit with my set-up? The fish I have now are hardy, but will more sensitive fish or inverts benefit from purer water?
I'll probably convert it to a reef tank one day and in that case, of course I'll get a RO/DI filter.
Thanks!
I'm not exactly sure what is in your water. You can get a water report from your local water department, and that will let you know more details about what they put in your water and what it contains. 50ppm TDS is actually pretty high, considering what we are aiming for is zero. Some municipal water systems add chloramines (about 1 in 5 households) to their water supply because it disinfects better and lasts longer distances. Chloramines are harmful to corals, even though fish can tolerate them below certain levels. 50ppm TDS also means that there could be heavy metals, nitrates, phosphates and ammonia coming through your tap water - that could contribute to algae growth and poor health of corals and or death.
50ppm TDS also means that your in pretty good shape to have an RO/DI unit as well that works efficiently. First, I would go with a trusted RO/DI supplier who knows what they are talking about and are willing to help design a system around your needs. Each municipal water supply, as I mentioned earlier, has their own additives, and having an RO/DI supplier that knows how to remove those compounds is essential.
For example, in my area I have soft water - with 500TDS and chloramines and heavy metals coming out of the tap. This means that I need a good sediment filter changed out monthly, two catalytic carbon block filters to remove chloramines changed out every two to three months , and a 75gpd membrane with a 98% rejection rate so that my DI resin is not exhausted so quickly. A good DI resin can remove about 6800ppm TDS until it's exhausted, so in my area that's right around every 109 gallons of water that I make.
Fortunately for you, at 50ppm TDS, you're dealing with only 10% of what I have to.
I will say now that it will be cheaper in the long run to go ahead and buy the refillable carbon cartridges and the refillable DI resin so that it won't cost so much to maintain. An automatic flush valve will also extend the life of your RO membrane.
Do I think it's necessary for the health of the fish, corals and inverts? Absolutely. After topping off for so long and doing water changes with tap water, your tank builds up levels of toxins, heavy metals and so on that could have easily been prevented by using the appropriate equipment in the first place.
