Water parameters for breeding.

[Broomha1]

Hi all. Complete newbie when it comes to breeding south American plecos, but its something I want to give a go. Over the past couple years I have acquired a collection of plecos and have enjoyed keeping them and growing them on etc. I want to take it to the the next level and gain experience in breeding. I have l046, l183, l397, l134 and l236 all over 3 years and of breeding size. My tap water is quite hard and I would like to work on it to get it right for the plecos. Tap water parameters are as follows...
Ph 7.8
Tds 349
Kh 6
Gh 14
I've purchased an ro unit which gives me...
Ph 6.3
Tds 6
Kh 0
Gh 0
If I was to go down the ro/tapwater mix route. What kind of ratio would i need to use? Not sure where to start. Thanks in advance

[Jools]

That's not so bad for tap water. Mine is pretty much the same; I store it in a large VAT and then use it after a few days. I don't need to use RO (although used rainwater when dealing with blackwater species breeding projects).

So, I can't answer the mix question from experience, but I would suggest you test your tap water after a few days and, also, if your tank(s) naturally drop pH over time to say pH 6, then adding water with pH7.8 may not be a bad thing.

Jools

[Broomha1]

I'm curious as to what leaving the water will do after a few days. I'll run a test, thanks

[Bas Pels]

TDS, GH, KH are all simple, linear measurements. That is, if you mix two similar amounts of water, one with 10 and the other with 20, the result will be 15.

pH is much, much more difficult, and apart from what it stands for, the value is also stabilised if between 5 and 9, the values we normally see. Therefore, mixing pH 5 and pH 9 can be anything, and the value can even change in the first 24 hours.

The best way to deal with this is
a) decide the value you want to have. Say 1/10th of the tapwater values
b) than you will need 9 units RO water and 1 unit of tapwater in order to approach this
c) measure the result, and add an airstone. Airate the water for 24 hours
d) remeasure the result. Most likely, the pH has been lowered. GH should be similar, KH can be different

This result will remain, even in case you would airate for another week.

Is this result OK - perfect. You just got yourself a recipe.

if this is not, the GH and KH can be changed by using more or less RO water

pH can be wrong, most likely it will be a bit high, if it is wrong. Adding some peat to the water might help.

Now you know how to prepare the water you need, next batch will be quite close to this one, if you measured everything carefully.

Use this in your water change routine, and slowly the tank water will reach this value.

pH will be the last to adapt, this is because your very tank is now at equilibrium with a certain pH, and lowering this will need quite a bit of acid.

And the problem is, you should never change the pH by more than 1 unit a day.

Therefopre you better not change more than 1/4th of the water. You could, however, change water every day untill the values are as they should be.

[Broomha1]

Thank you for your reply. Very Informative, and gives me a better idea of where to start. Now to work out what my desired parameters are for the plecos. I appreciate the help

[stuby]

I do a 50/50 mix of tap and RO..... peat moss, Oak leaves, or branches is a good way to get tannic acid in your tank if you don't mind water that can look like tea. I always age my changing water before hand... about 24 hours give or take. That way is stabilizes before adding it to the tanks.
I agree with the above.... the only way you know what your water is going to be like after mixing RO and tap is to do a experiment and see. I could have the same parameters as you do and we could get different readings in the end.

HTH
Chuck

[Broomha1]

Hi chuck
Thanks for the added info, very helpful. May I ask what your water parameters are after you've mixed your water and aged 24 hours? Thanks Dan

[stuby]

Hi chuck
Thanks for the added info, very helpful. May I ask what your water parameters are after you've mixed your water and aged 24 hours? Thanks Dan

GH-7, KH-5, TDS-135ppm, and PH-7.4.

[Broomha1]

Brilliant, thank you mate

[characinkid]

Interesting discussion.

I also put my tap water aside for 24hrs before using it, primarily to let it warm up a little and let most of the chlorine evaporate out. Im not sure that it does anything more than that, but I'd like to understand if it does?