pH rising...?

[aronson]

I don't get it...

For days my tank was sailing smoothly. Was seeing improvement in plants due to change in fert strategy started 2 1/2 weeks ago. Did a water change and massive pruning last Saturday.

Starting on Monday my pH began to climb. CO2 is still at full tilt -- 3 bubbles per second-ish and my plant guild mini vortex reactor is chock full of gas and water... Big bubbles forming/hovering underneath.

From 6.7 on Sunday it is now up to 7.3! Nothing has changed other than the water change... what could be at play here? What could cause the pH to rise? Do I need to reduce my surface agitation?

Adam

 

[Spar]

Re: pH rising...?

you need to figure out if something is leaching CO3 into the water (rocks, crushed coral, shells, etc) or if it is low co2 difusion causing the pH flux's.

do a water change, and then check your KH levels about 5 minutes later. Then when you see the pH rise again (24 hours later maybe), check your KH again. If a rise in KH occurs, then something is adding CO3 to the water which explains the pH rise.

if it isn't co3/KH, then it may be that your reactor is working inefficiently.

try to test that and then reply with the test result.

 

[Simpte]

Re: pH rising...?

Have you tested your water supply lately. Water companies tend to change things up as the seasons change.

 

[aronson]

Re: pH rising...?

Thanks for the reponses. Sorry its been a day or two...

The only two things that have changed in my tank over the past few weeks (as far as I can tell):

1) Temperature has droped ~8 degrees since late August.
2) I began using a powerhead to agitate the surface a bit. This should raise the pH a bit I would think due to more O2 exchange but should it account for a .5 climb?

No crushed anything that would add hardness. Not sure about the water company but what could they add that would cause the rise? When I did a water change on Sunday the pH post change was 7.0. Early Monday morning it was 6.7 but since then has started to climb. It is now (as of the time of this writing) 7.2!

I spoke to Bill at Plant Guild this morning and he offered to sell me a chamber to their Power Reactor as my current reactor is 'rated' (a loose term he told me) for up to 30 gallons. The Power Reactor is rated higher and has a larger chamber.

Any ideas?

Thanks,
Adam

 

[Tom Barr]

Re: pH rising...?

You can use a viewtainer that is 6" long from Orchard Supply.
Cost 2$

That's nopt the issue though, the increased surface movement, the KH of the tap.

That is where you should look.

Regards,
Tom Barr

 

[Laith]

Re: pH rising...?

Yes, check the KH of your tap water. Water companies sometimes change sources of water and this can mean big differences in KH...

 

[Jeff Bodin]

Re: pH rising...?

I had the same problem and I believe my issue is that I use a overflow and sump - while some say (Mr. Booth, I believe it was) that CO2 loss via overflow/surface movement is negligible I am doubtful.

I need about 5-6 bps to keep the pH around 6.7. Any less and I'm above 7.0 (DkH of 5-6).

- Jeff

 

[Tom Barr]

Re: pH rising...?

If the wet/dry section is sealed(you can tape it with duct tape also), the overflow reduced to about 3-4" drop, Return does not overly cause surface movement, then it should be no different than a surface skimmed canister.

Regards,
Tom Barr

 

[aronson]

Re: pH rising...?

All,

Thanks for the suggestions!

Increasing the bubble rate wont help me at this point as I am already overflowing the vortex reactor's chamber. If I push any more gas into it bubbles start to pop out of the sides.

I am still wildly skeptical about the KH change but I am also humble enough to believe it. I'll test today or tomorrow.

And, I'll ask once just to clarify... Can water movement at the surface really account for such a large swing in pH? We're not talking rapids and crashing waves, just some minor rippling.

I've posted here before that I have a wicked time keeping my pH as low as I have (6.7) so I am inclined to think that the inefficiency of the vortex is complicating the additional issues fellow posters have mentioned here. I'll make som changes and report back.

One last thing... What part (if any) might an 8 deg temp drop play in all of this?

Adam

 

[fosteder]

Re: pH rising...?

Adam,

I don't think the temp change has any part, but I could be wrong.

As far as your surface movement question, yes it can affect it that much. I went from not much surface movement (19 bubbles per minute, KH7, Ph6.8) added a little surface movement (just ripples from spray bar) and suddenly my 19 bubbles per minute only got me to 7.4 to 7.5. I had to up the bubble count to 80 bubbles per minute to get ph back down to 6.8. Sounds like you need a better reactor.

regards
Derek