RO/DI top off and algae scrubbers

[new2scrub]

I was wondering if you could get away with lightly filtered tap water for you top off water if you have a mature ATS. Rather than replacing my $60 membrane maybe I could just run 1 sediment filter and 2 carbon block filters on my RO unit and bring my TDS down to about 15-25 (I have pretty good tap water) maybe the extra minerals would help the algae??? just a thought........

[SantaMonica]

A scrubber (algae) does remove most of the "bad" things in tap water (after all, algae does all the filtering in lakes and oceans), but it is not known yet if they are ALL removed. And what certainly is not known is if they are removed fast enough for you to put tap water right into your tank for top-offs (it's already assumed that you are not doing water changes anymore, so we are not talking about adding huge amounts of tap water at once; just small amount via top off). Chlorine is definitely not removed by algae, but chlorine will, in tiny amounts, evaporate as the water is circulated in the system. Chloramines (chlorine + ammonia) do not evaporate, but fortunately they are broken apart by ascorbate and ascorbic acid, both of which are produced by algae. After the chloramines are broken apart, the chlorine evaporates and the ammonia is eaten by the algae. Again the question is if this is done fast enough.

Some people are experimenting with using tap water instead of RO or RODI, but there are few results yet. I myself have a test 10 gal FW nano that I top off with tap (unconditioned), and for over a year it's been doing great. I pour in about a 1/2 gallon of tap water at a time. I also put small amounts of tap into my reef, but not enough to call it "top off".

If you have live rock, or live sand, or any corals or inverts at all, your problem becomes copper. Copper can occur in city water or in wells. Yes a scrubber (i.e., algae) consumes copper, but the question is will the copper be removed fast enough so that no damage occurs. Nobody has tested this, so it would be an experiment. The best test would be to start with an new tank, and add your corals or inverts one at a time (cheapest first).

If you do add tap water, do it the day before you clean your screen, so that you have the most algae possible.

[new2scrub]

i see... well maybe i will try to top off my f/w bass tank with tap for a while and see how that goes. I just got my reef tank perfect so i wont mess around with that one just yet... by the way santa the larger pump on my reef tanks scrubber made all the difference in the world.. no more film algae on the glass! thanks!

[SantaMonica]

Way to go :)