When people use RO water for breeding, is it straight RO water or do people remineralize it?

[Yanni]

I am thinking of getting an RO system in order to breed some South American fish and I've seen that a lot of people use RO systems. Do people have to remineralize the water as well? 

[Fish Folk]

Some species can take neatly pure RO water changes for spawning, but some  breeders target a TDS level, and either (1) remineralize, or (2)  _mix_ RO with source / tap water to achieve desired results.

If your KH is down to 2-3 drops titration, you can probably not bother with RO for most SA species. Discus can be tricky…

[tolstoy21]

On 11/7/2022 at 1:55 AM, Yanni said:

I am thinking of getting an RO system in order to breed some South American fish and I've seen that a lot of people use RO systems. Do people have to remineralize the water as well? 

The answer is 'it depends'.

For caridina shrimp I remineralize RO water to their specifications. 

For a few other species I do use straight RO water (with leaves and peat added) because they are true blackwater diehards and will only spawn in a Ph down in the 4's in water with very little mineral content.

I have well water with 0Kh (my Gh is about 9), so my Ph naturally sits in the low 6's. This is fine for the majority of the fish I breed, and one of the reasons I try to stick with fish that appreciate acidic water.

However, if I had a different water supply to work with that had a higher Ph, then I would go the RO + re-mineralizers route (or RO cut with tap water). 

So whether or not to use RO, and whether not to re-mineralize is situational.

 

[DiscusLover]

On 11/6/2022 at 10:55 PM, Yanni said:

I am thinking of getting an RO system in order to breed some South American fish and I've seen that a lot of people use RO systems. Do people have to remineralize the water as well? 

Depends on how you want the hardness to be. You can mix your tap with ro water which I do and match a certain tds. Most SA fish will breed in a tds of 50-100 and I aim for around 70tds (currently breeding angels and rams)