Backyard Aquaponics
A place to discuss aquaponics

Hay guys, do keep in mind with your advice that his containers are those vertigrow stacks so they do not flood. He essentially has a trickle feed through his gravel but the containers never flood. Having a timer on things might be ok but I wouldn't have the off period very long during the hot part of the day as the gravel will only hold a small amount of moisture.

Here in Florida, you can get fish safe nutrients from Aquatic Eco Systems.
http://www.aquaticeco.com/subcategories/3429/Pond-Flourish/S2545/0
Unfortunately, they don't seem to be carrying the separate potassium or Iron anymore. I have tried this stuff and the plants do seem to perk up a few days after I add a dose but it is $$ and I think I should be able to find a better way.

Liquid Iron (Iron Sulfate) is pretty inexpensive to make a foliar spray for the plants.

I've tried the banana in the grow beds but my grow beds are big so they probably require more than I put in. A small amount of potash to provide potassium could work but care must be taken since it will raise the pH.

TCL - potash will raise the pH????
Why didn't I think of that! Cheers
But how do I work out how much to use?
Sorry for the Hijacking art.

http://www.gardenendeavors.com/rack/perfectwater.html
Here is a link where I saw them saying...
"Potassium is another important chemical your pond may need. Purchase muriate of potash, and add a tablespoon per 1,000 gallons each month during the summer and you will see lush green growth in your water hyacinths and other water plants. There is also evidence that potassium helps fish growth as well."

So a tablespoon per month per 1000 gallons. This site is more about ornamental ponds but it looks like a good starting point. You want to be careful with the muriate of potash (potassium chloride) as it will raise pH. Also, if you have already salted the system for some reason, you might wind up with more chloride than you want. But if you haven't already salted, the potassium chloride has the added benefit of the chloride helping to protect against nitrite toxicity (not generally a problem once a system is cycled though.)

As for using it to specifically raise pH, I don't know how long the effect would last. It might be better to use potassium bicarbonate for that purpose.

Then again, there was some one on the forum not too long ago that had mixed wood ashes with water and added them to their system. Yep wood ashes will have some good stuff but they are also caustic and will raise the pH big time. Perhaps they are pretty safe for dirt gardening but in AP, wood ashes would need to be used in extreme moderation.

Mmm... cheers TC, today I added mega salt!
But thanks for the heads up!

Potash is a VERY powerful basic compound. If it were me (and it isn't) I would grab a sample of water (20l/5gallons or so) and carefully, using the potash, take it to the pH I wanted. From there, one could calculate (guess) how much the entire system would need and add maybe 10-15% of what is guessed and check after a few hours. They could then add a bit more as necessary.

I would not add directly to the fish tank and I would bring the pH up over a few days.

Ron

But remembering that this is Art's thread and he has the opposite problem. His pH is too high (due to limestone probably) and he needs way to slowly/steadily bring down his pH and keep it that way.

Not sure if this has been mentioned but be careful of large pH changes...if you keep the changes to <0.25/day (rise or fall), then the fish will have time to adapt and remain happy...wdy's idea of 10% dosage is a good guide