Getting The Very Best Nano Tank Water - Ro?


New Member
May 31, 2014
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Hello All - I'm new here. We have just bought a couple of nano tanks and we are both lucky enough to work in laboratories. This gives us unfettered access to grade II laboratory RO/DI water and water test kits, which is good given our local water isn't ideal for tropical tanks. We'd like to do the best possible by our fish (we really do care!), so my question is: given our access to RO/DI water and tests, what would you do to maintain the best possible conditions for our fish? At the moment we are changing water with 1:1 lab water and tap water mix to soften it. I'm interested in using 100% RO/DI water and adding hardness, nutrients and buffers as required, but I'm not confident with the correct mix as yet. Any suggestions?
Details are:
Tank details:
Fluval Edge 46l, heated, with fine gravel (coarse sand) substrate, bogwood, planted. Stocked with 1 dwarf gourami and 10 neon tetras. Gravel hoover and 30% water change every 7 days, 1:1 mix of RO and tap water with Aquasafe & a liquid plant fertilizer. Filter with carbon removed and polishing floss added. A second undecorated tank (22l) is for quarantine & treatment at the moment, and currently houses a poorly dwarf gourami. If he survives, it will probably be decorated and become his home.
Last tank water results:
Acidity: pH 7.5 (Palintest)
Hardness: 7.7 °gH, 7 °kH (Palintest & Sera Aquatest respectively, German degrees)
Phosphate: 2 mg/l (Sera Aquatest kit)
Ammonia: 0 mg/l (Sera Aquatest kit)
Nitrite: 0 mg/l (Sera Aquatest kit)
Nitrate: 10 mg/l (Sera Aquatest kit)
Temperature: 25.5 °C
Local water:
Acidity: pH 8 (Palintest)
Hardness: 11 °gH, 12 °kH (Palintest & Sera Aquatest respectively)
Phosphate: 2 mg/l
Nitrite: 0 mg/l


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