My L.A. County tapwater is very hard (8dKH, 12dGH), alkaline (pH=8++), has recently been turning in about 20ppm of Nitrates, 0.5ppm of phosphates and God-knows-how-much of silicates. With fishload, even with a planted tank, I'm finding it difficult to maintain 40ppm of NO3 (API test), so my cherry shrimp are not breeding and are often hiding and not even surviving too well. So I'm thinking of getting RO+DI water.
However, now I'm in new territory with confusing information from different sources. Could somebody please help me summarize or select the ideal additives for weekly 40-50% water change with RO+DI water?
Here are the details:
Size 80g, 48in x 18in x about 21(?) in high, 60g water column, planted.
Plants: 2 large Swords, 4-5 Cryptocorine, 2 Bacopa, 2 Cabomba (not doing very well), 3 Red Ludwigia (turning green at new growth), patches of Glossostigma (not doing very well), Tears, 1 large + 1 small Windelov fern, some Java fern, some Fissidens moss, and lots of floating fast-growing Pennywort to provide shade to the Windelovs and try to take out some nitrates.
Decorations: Mostly dark black wood, don't know exactly what kind of wood, plus a couple of lava rocks.
Stock: 6 Zebra/Leopard danios, 10 Rummynose Tetras, 10 Green Neon Tetras, 6 galaxy rasboras, 2 dwarf powder blue gouramis, 5 Otocinclus, 1 Stardust Plecostomus, 10 amano shrimp, 10 red cherry shrimp, 10 yellow shrimp, and countless Assassin snails (>30 after I threw about 30 out, and breeding prolifically from original 4!).
Lights: 4 x 54 watts T5 HO
Current water parameters (all API tests) using tap water:
NH3/NH4=0 ppm; NO2=0; NO3=40ppm; dKH=8; dGH=12; pH=8.2 before CO2 injection; pH=6.6 with CO2 injection during daytime; Dosing mostly with Potassium Sulphate and chelated Iron. [Trying to use EI results in too-high phosphates & nitrates.]
CO2 injection as indicated above with pH discussion.
Filters: One Fluval 406; One Aquaclear 70 powerhead Quickfilter with Seachem Matrix behind the polisher pad; One Aquaclear 20 powerhead Quickfilter with Seachem Matrix behind the polisher pad.
Trying to change to: RO+DI.
Any advice will be appreciated, even if (especially if) you disagree with my inferences/conclusions/assumptions. I would especially like to know what combination of Seachem Equilibrium/Replenish or anything else I should routinely add to my RODI water to maintain optimal buffer and oiptiomal Ca + Mg etc.
By the way, what is the optimal level of KH, GH, I should shoot for? I was thinking pH=7.0; dKH=5; dGH=7 or 8 ? Does this sound appropriate?
If there’s an excellent RELIABLE thread that I should look at, please feel free to just provide the link. Thanks!