PH in Rock Wool Won't Come Down?

This is the loose bulk rock wool. I soak it for a day and a half had the water ph to 5.0 then when you put the rock wool in the ph goes right up in the sixes then I added more ph down till I lower it to 5.3, then ph would go in to 6.0 something. I did this a 3 times maybe I should of done it more! I thought they needed to be fed so I fed'em alittle soon ph the nutes to 5.3 and 600 ppm but the run off was 7.0 ph & 500 ppm whats up with that? This was after I flushed with a whole gallon of stuff! So I have some pertyiness with a mild drooping going on Is this from water too soon or the high ph? Or does the run off ph mean anything? They look pretty healthy one has a little algae and one leaf has a really dark green spot.

Rock wool is limestone rock...lime has a very high ph. Most of us soak our rock wool for 12-24 hours in water ph'd down to about 3.5-4. By the time it is finished soaking it should be about leveled out around 5.5-6.0.

No, nothing really hurts the rock wool. I've never really grown like you are right now, I usually just use a cube, and surround it with hydroton to improve the draining capabilities of the rock wool. Also if you don't cover the top of that rock wool you are going to have some serious algae problems.

Wow, I guess I didn't know I had to be so diligent in the balancing my rockwool, is it different when using cubes vs. shredded. I use the Grodan product and when starting seeds I just PH some water to 5.5 soak the cubes for 10-15 min then shake off the excess, put in germinated seed and water with 5.5 after a few days and then only to keep the cube moist. When I transplant from my aerocloner, I take 1.5 cubes and soak them for 10-15 min in 5.5, split them in half, gently insert rooted clone, then press into 3.5 cubes with holes for receiving the 1.5's. The cubes get the same treatment then they get placed into net cups with hydrotron. If the ph hits 6.1 I"ll ph down it to 5.5 otherwise I leave it alone and I watch it pretty close and it usually only drifts slightly.

I use GH nutes so they help buffer also I would imagine. How do you prevent algae from growing on the top of the rockwool as I cover all my cubes in the later stages to prevent growth, as this will help prevent stem rot. I don't think they look that awful and perhaps your chasing the ph a bit to hard?

BTW, what are you using to adjust you ph with?

Are you seeing alot of deformed and twisted growth? A sign of radical PH swings according to the plant problems thread.

pazuzu420 said:

Are you seeing alot of deformed and twisted growth? A sign of radical PH swings according to the plant problems thread.

Click to expand...

No twisting maybe slightly deforming~

Normally you don't have to be so diligent because in most hydro set ups the cube is constantly bathed in ph'd nute h2o and then we adjust the recirc rez every day or so until ph balances out. However, it looks like his plants are just top fed with no recirc, which means the ph is going to react just like soil (kinda)...making it more important to take care of it before he starts.

I'm thinking I got the wrong and cheaper rock wool I'm starting over. I wasted 2 weeks oh well, I went to the grow shop and I got the good rock wool it cost a little more but if it works~This stuff is the same as the cubes.