Friday's AP system

[Frydaze1]

Hey folks. I had planted a bunch of seeds in rockwool, and the hydroponics guys said that I could put the squares directly into the growbeds. And THEY said it wouldn't hurt the fish. But I'm learning that experts on one side of the aqua/ponics equation seldom know anything about the other side.

So can I please get an opinion from the people here who actually DO know aquaponics?

TIA!

[Rew]

Rockwool won't hurt your fish, but it does have a rather high ph, and its recommended to soak it in a low ph water before using. I use a spoonful of vinegar in my water here before soaking them. I have used them without soaking, and to be honest it didn't matter for the tomatoes. Perhaps some plant types wouldn't like the high PH as much.

[Crusty]

From a fish point of view, no issue at all with rockwool as Rew has said. It is just rocks with some starch binders.

[GaryD]

Hi Fri,

But I'm learning that experts on one side of the aqua/ponics equation seldom know anything about the other side.

An interesting observation from someone so new to the craft.......and a worthwhile one from the point of view of anyone contemplating a commercial operation.

I'm frequently amused at how some people actually believe that the combination of aquaculture and hydroponics somehow makes the need for knowledge about either, superfluous.

Gary

[Frydaze1]

Rockwool won't hurt your fish, but it does have a rather high ph, and its recommended to soak it in a low ph water before using. I use a spoonful of vinegar in my water here before soaking them. I have used them without soaking, and to be honest it didn't matter for the tomatoes. Perhaps some plant types wouldn't like the high PH as much.

The hydroponics guy had told me to douse the rockwool with boiling water prior to using it, so hopefully that helps. But since I didn't lower their PH before using them, I'll be sure to transplant with some vinegar water (which I'm already dosing with for my high PH). I was mostly worried because the rockwool feels like fiberglass to me the way I always have to wash after touching it or my fingers feel prickly. So I was worried they would shed fibers into the water that would irritate the fish.

Hopefully soon I'll learn to come here and ask questions *before* trying something, instead of thinking of all the potential consequences afterward.

I'm frequently amused at how some people actually believe that the combination of aquaculture and hydroponics somehow makes the need for knowledge about either, superfluous.

Well all the hype makes it sound like the symbiotic relationship between the fish and the plants takes care of most of the technical aspects for you, and you just have to keep the fish fed.


Thanks, guys, for your help!

[Frydaze1]

I'm fighting high PH, and I have to believe it's the rockwool. I keep getting it down around 6.4 and 24 hours later it's almost to 8 again. I can't think that using this much vinegar in the system is good for it, aside from it not holding long enough to be worth it.

So I think I'll pull out all of the rockwool cubes and soak them, seedlings and all, in vinegar water. I think I'll just manually do soak and drain all day tomorrow so they get enough air and water. Meanwhile, I'll change 1/2 the fishtank water, get it down to 6.8ish where I want it, and monitor it to see if it stays stable without the rockwool. If so, I'll try putting the soaked cubes back in and see if I've stabilized them enough.

If that doesn't work, I'll try to pull the seedlings out of the rockwool and plant them directly in the hydroton, if I can get them out without damaging them too badly.

And if THAT doesn't work, I'll seed directly and start from scratch.

I'm glad I started small. It would be devastating to me to learn all this stuff on a big system.

[Crusty]

Check your alkalinity (KH). You can get little kits for that at the aquarium shop.

[Frydaze1]

Okay, explain alkalinity to me, please. I thought it was simply the high end of PH, meaning the opposite of acidity.

[Crusty]

Okay, explain alkalinity to me, please. I thought it was simply the high end of PH, meaning the opposite of acidity.

It does get a little confusing with some people referring to the "Base" end of the pH scale as "Alkaline". Without going into it, Alkalinity helps prevent pH swings like the ones you are having. You will find you have little or no alkalinity.

[Frydaze1]

Okay then. How do I increase the alkalinity of my system without increasing the pH?