PH rising problems

[Rattrap]

Hi all, i'm having some problems with ph rising.

I'm running a bio-bucket or DWC system - 500L, the same system i've been running for a few years now. Never had a problem with unstable PH till the last couple of grows.

I've been using the same nutes, Dutchmaster gold (their full range used at their recommended levels) for the last couple of years too, nothing has changed with regard to the system or the nutes.

I run a 6800Lph pump that turns the water in the buckets over about 10 times an hour plus each individual bucket has its own airstone.

Water temp is a balmy 21-23c.

Now when i mix up a fresh batch of nutes i adjust the PH to around 5.5 - 5.8 as recomended by DM but within 12 hrs the PH is up to around 6.8. It takes a fair amount of PH down to pull the levels back down to around 5.8 even tho the TDS is only 450 (new plants). This will go on thru the entire grow even as the nute levels rise. After 12 hrs its up around 6.8 - 7 again. This goes on for usually round 5-7 days when it stabalises for a couple of days then turns & dives the other way to round 4.5 -4.9 & requires a fair amount of PH up to pull it back up.

My water supply is mountain fed water with a ph of 7.1 & a TDS of 20

In the past i've had to use little PH up or down thru an entire grow where as now i am going thru easily 1L of both PH up & down.

Its got me buggered why this is happening, i was tempted to change to a different brand of nutes this grow but i always have such damn fine results with DM that i chose to stay with DM for this run.

Edited March 10, 2011 by Rattrap

[Rattrap]

ok, after a bit of a talk with some guys in the oz stoners chat room i think i've sorted out my ph issue.

I use red lava rocks for my medium & after 1 of the guys in chat asked me if i use silica cuse silica can raise ph, i remembered reading a long time ago that red lava rocks are highish in silica & this run i started using a fresh batch of red lava rocks. After doing a full nute dump & refill but without the DM silica my ph is now taking 2 days to rise from 5.8 to 6.3 so i think the problem is solvered.

Many thanks to the guys in chat who helped with suggestions. :thumbsup:

[starpo]

ok, after a bit of a talk with some guys in the oz stoners chat room i think i've sorted out my ph issue.

I use red lava rocks for my medium & after 1 of the guys in chat asked me if i use silica cuse silica can raise ph, i remembered reading a long time ago that red lava rocks are highish in silica & this run i started using a fresh batch of red lava rocks. After doing a full nute dump & refill but without the DM silica my ph is now taking 2 days to rise from 5.8 to 6.3 so i think the problem is solvered.

Many thanks to the guys in chat who helped with suggestions. :thumbsup:

 

 

So helpful are these guys, i to got my PH issue solved! Go OZS