ph swing 7.9-8.35 measured with acjr

[bluetang_2000]

At night with the refugium light on, the ph value is 7.9, and 8.35 during the day when 2x175w metal halides & 2x110 pc are on. Is this ph swing acceptable? I am also using osmolator to dose kalk water from a brute can.

[jdieck]

That swing is unusually large. Try switching your Kalk to drip only at night to compenase a bit more. Also check your alkalinity level, try maintaining it at around 10 dKh (3.5 meq/lt) If the alkalinity is low there will be more tendency for larger swings.

[bluetang_2000]

I don't drip the kalk. After mixing the kalk water, then I pour the kalk water into the 18gal brute can with freshwater. Any problem with this setup if I only turn on the osmolator at night to top off the evaporated water with the water from the brute can?

I'll check the ca/alk/mag level tonight or tomorrow.

[jdieck]

Yes you need to install a timer on the osmolator. Note that you may need to restrict the powerhead flow so when the system starts it does not dump the whole day's evaporation at once. Ideally you may want to use a doser pump rather than a powerhead.

[itreef]

What is an acceptable pH swing? My swings from 8.1 at night to 8.35 during the day on a 30 gal tank with 10 gal sump and 10 gal fuge. The fuge light is on all day.

[stony_corals]

pH is going to swing, based upon your stocking levels, params, etc. You can't stop it, just make sure your alk is in line and you'll be fine. I don't pay much attention to pH. I've my AC3 set to turn off the solenoid from my Ca Rxs when pH hits 7.8, but that hasn't happened.

[bluetang_2000]

Thanks for all of the replies. I did some test last night, and here's the parameter,

ca - 420
alk-6.24dKH
Mag - 1000

Seems like I need to bring the mag level higher. Ca/Alk seem ok?

[GMAX]

Just over 6 dKH? That is too low. I think your minimum would be about 7, and many reefers run it much higher ( 11 to 13) as it has some beneficial growth rates. I would say you need to start dosing some baking soda each day until you can raise your ALK up to 9 or maybe even 10. Dont try to raise it all at once, it could shock your inhabitants.

[Billybeau1]

<a href=showthread.php?s=&postid=9791574#post9791574 target=_blank>Originally posted</a> by ryguan
Thanks for all of the replies. I did some test last night, and here's the parameter,

ca - 420
alk-6.24dKH
Mag - 1000

Seems like I need to bring the mag level higher. Ca/Alk seem ok?

Yes, as Gmax said, if your test kit is accurate, your alk is too low.

Get yourself some good old Arm & Hammer baking soda (not powder) and dissolve it in fresh water. This calculator tells how much to dose.

Then work on getting your mag up. You can either use the homemade brew or I use Kent Tech-M

Use the same calculator for that.

http://home.comcast.net/~jdieck1/chem_calc3.html

[bluetang_2000]

Thanks all for the advice. seems like I'll have to work on the alk and the mag.

[Billybeau1]

:thumbsup: