Quote Originally Posted by bcotton
Personally, I do aquaponics more for the plants than the fish and i try to keep my ph just below 7. My expanded shale is supposed to be neutral but it appears to be buffered to about 7.8. I buy "ph down" from a local hydroponics store for about $30 a gallon. It's mostly phosphoric acid and the fish do not seem to mind it.

I add it in 30-50ML increments to my ~400 gallon system.


Brian
Gotcha. Then you will want to go closer to 6, but since you used expanded shale you are really up the creek without a paddle...

As we all (should?) know shale contains calcium compounds including calcium carbonate (commonly used to bring pH up). Unfortunately, shale is advertised and sold as an inert aggregate. I have some sample with me and was planning to do a "neutralization test" and post the video results for all to see. Don't get me wrong, having shale in your system and keeping your pH between that 7.2 to 7.8 at all times without doing ANYTHING can be VERY NICE. However, it's not what YOU want in YOUR CASE. That's unfortunate, and for the misinformation out there, I apologize on the communities behalf. Silly folklorist aquapons...

EXAMPLE (everyone makes this claim, do not blame the seller since the supplier is who passes this info... I think...)


What I don't understand is why it would blatantly state limestone is bad, yet shale is clearly made from the compression and heat over time of limestone... in other words, shale is made from limestone and maintains significant quantities of the same chemical compounds found in limestone... Am I crazy or does this make sense to anyone else?

I will conduct the experiment next week and record it for everyone. I hope at that point everyone will be clear on this seemingly obvious topic...