Rockwool and PH?

[smookless]

Hey all, I moved over to an ebb and flow sys, with 6x6 rockwool cubes. I am having trouble keeping the PH at or about 6.0. I am on day 4 with my clones in the cubes. I start the Res. at 5.0, water 3 times a day for 15 min and by the end of the day the PH is 6.5-6.7. the water PH in the cube stays consistant with the Res. Is this normal? do I just keep lowering the PH everyday? is there something I need to do to keep it level? and yes I pre soaked the cubes in 5.5 PH water for 24 Hr.

smookless Reviewed by smookless on 02-10-2007. Rockwool and PH? Hey all, I moved over to an ebb and flow sys, with 6x6 rockwool cubes. I am having trouble keeping the PH at or about 6.0. I am on day 4 with my clones in the cubes. I start the Res. at 5.0, water 3 times a day for 15 min and by the end of the day the PH is 6.5-6.7. the water PH in the cube stays consistant with the Res. Is this normal? do I just keep lowering the PH everyday? is there something I need to do to keep it level? and yes I pre soaked the cubes in 5.5 PH water for 24 Hr. Rating: 5

[LOC NAR on probation]

Keep adjusting, they are young and I think it will level out. Also what kind of nutes and water are you using ? Some nutes will buffer better than others but sounds like your doing good

[smookless]

I started them on G.H. floranova, 200 ppms. Reverse osi sys. water starts at 15ppm. How many times should I be watering with this system? is 6.5 PH ok? Should I move to watering just twice?

[deftdrummer]

Watering just twice might be a bad idea. Your plants are young but as they get older they will take up more water and nutrients. It sounds like your setup is doing just fine. Your pH is going to fluctuate daily and it is not uncommon to have to pH your system as many as 4-5 times a day sometimes more if your nutrient solution is close to needing a change.

To answer how many times you should be watering - there is no way to really tell without knowing the system. Since you know the system best you should experiment to dial in the correct schedule that works for your individual system. A good way to do this is to intentionally over water (something like 5+ waterings a day during flowering and 8+ for vegetative growth). This is just a rough guide, but once you start to see the first signs of over watering like wilting, you know to back off by one to two waterings. Since every system is different.

ALSO, you need to account for the time it takes for the tray to drain. For our system water kicks ON at 8am and OFF at 8:10. It takes our system another 10 mins to drain completely so we go 4 hours between waterings from the time of complete drain ie: 8:20. If you add up all the drain times it is easy to see that if you go 4 hours from the time of SHUTOFF that your roots will be exposed to just a bit too much water.

[lmdesade]

I started them on G.H. floranova, 200 ppms. Reverse osi sys. water starts at 15ppm. How many times should I be watering with this system? is 6.5 PH ok? Should I move to watering just twice?

That's kind of funky... Yet, floranova is suppose to be ph stabilzed which might be part of the problem...:thumbsup: