Remineralising and KH

[craftycarp]

Hi all, I wish to remineralise RO for breeding purposes. I have preis minerals (popular in Europe) but what I'm concerned about is the lack of KH. Preis minerals do not raise the KH at all (unlike JBL aquadur which will give me a KH of 2 dkh) I will be doing 50% water changes per day. Is this enough to not worry about the KH? I am curious as to how people do this as I know preis are a well trusted product?

[Willie]

I've been able to successfully spawn discus in 100% R/O and raise the fry in straight tap water with no problem. I do not recommend remineralizing. Frequent water changes are far more important to raising healthy discus and also makes remineralizing problematic.

[craftycarp]

This is kind of what I was thinking too. So as long as I'm keeping up with plenty of water changes, don't worry about the KH? Appreciate your input

[Willie]

Stability of water conditions is far more important than a specific chemical parameter. If you're doing a lot of water changes, the quality of your water remains constant. Good luck, Willie

[peewee1]

Adding up all of the years that I have raised and bred discus I did not know what KH was. Finally a few days ago I read about it. Which in turn gave me the notion to head for the lfs to obtain a KH test kit and the bags of crushed coral for the the filter. As you know if change about 15% per day using tap water. The tap is 7,8 pH and the tanks normally maintain at 6,8 to 7.6. Now reading Willie's post I'm tending back to just leaving well enough alone but I would like to lower the pH a little bit in the breeding tank that I set up 2 weeks ago and then think about the KH should the pair spawn and should I find that the eggs are not fertilizing or hatching. Any thoughts?

[Willie]

Hardness comes primarily from calcium and magnesium in the water, typically when the water column is exposed to limestone. Calcium and magnesium salts are only slightly soluble. As water cools, these salts come out of solution and coats the inside of water pipes. They also do other things like disrupt detergent activity, add off-flavors, etc. Water softeners address this problem by adding more salt to the water to flush out calcium and magnesium. So softened water is a marketing term, i.e. there's nothing soft about it. Softened water will have higher KH than unsoftened water, because sodium has been added to the calcium and magnesium. If you're running R/O, tapping water ahead of the water softener is preferred so the membranes don't have to deal with added sodium.

When discus spawn, high calcium in the water prevents sperm from fertilizing the egg. So low calcium, low KH, water is needed during spawning - no other time. Spawning takes ~45 minutes, so that's really the only time in the life cycle of discus that high KH water causes problems. When my pairs started to clean the cone, I would just make a big water change with R/O water. I used to buy this at a LFS and kept it in the fish room. The pair typically spawned within 2 hours of the water change (R/O water will stimulate spawning). After the spawning process, you can go back to hard water with no problem. Hatching will be normal, fry development will be normal, juvenile growth will be normal.

Most discus books do not explain the process accurately and readers make inferences about soft water requirements. I've had so many fish store employees tell me that I need to buy their R/O unit to raise discus that I no longer argue the point. Hope that helps.

[coralbandit]

I mix my RO and my tap to get the TDS I desire for my fish .
TDS and regular water changes are what you want to control .

[craftycarp]

I mix my RO and my tap to get the TDS I desire for my fish .
TDS and regular water changes are what you want to control .

I was doing this to start with but my tap water is so hard I was using 90% RO to 10% tap. In then end I thought I might as well just use 100% RO and add minerals

[coralbandit]

I am mixing 80% ro with 20% tap for my rams [ gets me 100 TDS] and even less tap for the discus .
My main point was TDS is the measurement you want to watch and the one you can effect on a consistent controlled basis .
You can not raise KH without raising pH ,usually GH and definitely TDS..
KISS works real good for me !