RO or Tap Water for tropical tank?

[Fishless cycle]

I'm undecided about whether to continue with RO or go back to tap water for my two tropical tanks.

Which is better for fish? I test my tap water regularly and nitrate is around 30ppm on a good day or 40ppm on a normal day and that's before adding it to the tank.

What advantages are there of using tap over RO (and vice versa)?

I will add more live plants and I've also got a filter bag to absorb the nitrate in both filters.

Any ideas, advice or suggestions would be much appreciated??

 

[librarygirl]

Are you repleneshing the RO water with minerals? The thing with RO water is that it's stripped of everything so the minerals need to be replaced with something like Kent's RO Rite or Seachem Replenish.

SInce your nitrates are borderline high, you could use half tap and half RO which would cut the nitrates by half and remove the need to replenish the water with minerals.

Some with high nitrates use Purigen in their filters to absorb the nitrates. Fast-growing stem plants like hornwort can help too.

 

[Fishless cycle]

Thanks for this. I've been adding minerals but I've also noticed that the kH in my tanks is really high at 11 degrees in one tank and 12 in the other so I've done a pwc with pure RO... Just 10% to get the kH down and not too much to stress the fish.

Gosh if it's not one thing then it's another! It's a balancing act at the moment. I want my pH to stay as constant as possible. I will try mixing the RO and tap water once my kH is back at around 3-6 degrees... That's right isn't it for tropical and in order to keep the pH level stable?

This mix of RO and tap water should help reduce my nitrate too then. Thanks