Controlling Diurnal ph swings

[cilyjr]

Think I can control diurnal ph swings using kalkwasser at night?
Tried with dosing with a brs 1.1 during the swing but it's too slow. Using saturated kalkwasser at 2 tsp per gallon.

I'm not worried that much about alk or ca level rising by this as I always seem to be on the low side of ok...

 

[this is me]

Running your refugium light in the reverse cycle of the main light will also help. I've been doing this for years but I never pay too much attention to PH swing. My PH range is 8.0-8.3 for the past 90days.
When I was dosing, I had it up to 8.5. Now with the CA reactor, the window is tighter. Haven't noticed a single thing different in the tank.

 

[IPWitan]

Curious on what the swing is and how/why that is bad. I don't have a way to monitor my ph accurately so I don't know what my tank is doing in this regard. Notwithstanding, I run my refugium lights all night long and do my 2 part dosing at 3 different times - two of which are in the dark hours. I also dose saturated kalk - two points are in dark hours. For kalk, I dose about 1/2 my ATO rate, and let the ATO handle the rest of the evaporation. With dosing pumps, the inputs are constant. With kalk in the ATO, it becomes a variable.

I am curious if you tried some of the common techniques and your results. Anyone who uses the word "diurnal" in their post is clearly a scientist who has done some experiments. That means you have knowledge from which I can learn...

 

[cilyjr]

Nick.
I don't have a fuge as I believe the refugium required to recieve any real nutrient export benefit needs to be as large or larger then your display.

My ph swing goes from 8.1 to 7.7 (ish).

I run a ca reactor as well but have been unhappy with it of late.

 

[cilyjr]

I'm gonna get some chaeto just to see if I can get the phone swing down
This will be in addition to adding kalkwasser

 

[nemodan]

For years it has been in this way my ph and i was never worried about it. I do have a fuge too. Big one, but it cycles with the tank cycle. No reverse cycle.

 

[cilyjr]

I guess I should clarify my intentions. My biggest concern is that the swing goes below 7.9. I suppose I could add a consistent kalk drip which would bring ph up all around. But if I can lessen the swing and bring ph up why not

 

[this is me]

If you have low PH, it's an air exchange issue. If there's a feasible way to plumb a 1/4" air line outside and connect that to the air intake of your skimmer, it will help tremendously. But do keep in mind that if the air line is near an exhaust or anything that caused polluted air, you will have issue keeping your livestock alive.
7.9 would not be a concern of mine. 7.6 maybe but 7.9 is plenty high.

 

[frank180reef]

Open your window today

 

[cilyjr]

no i've always had lower ph.
and I had the Skimmer pulling from outside at 1 point. but stopped when it became clear that skimmer performance was inhibited due to the length of the pull. i could do this again uusing a larger diameter hose but
my ph has always been lower from 8.14 high to 7.75 low. thats the swing.

ideally I'd like to see 8.2 to 8.0 for swing.

I got some chaeto today...not much but will get it on a reverse cycle and drip kalk at night and see if that helps....I also did some fine tuning on the ca reactor (I neglected it recently and allowed the controller to just dump a bunch of co2 in then shut off quickly. this made the reactor go from 6.8 to 6.7 in about 1 min then shut off then 10 mins later the same). i hope fixing that will help. also the effluent was not dripping properly. it would drip very fast then slow to almost nothing...repeat... I don't think this was contributing to the diurnal swing (probably helped with my stn issues though due to unstable alk)but it needed fixing.

 

[bill120mph]

have you always had a cal reactor? to much co2 maybe?

 

[cilyjr]

Yes and that sure has something to do with it. I added a 2nd chamber a few months back to help and it did some

 

[nemodan]

May I ask a simple question :

Are you having trouble with your corals ?

If the answer is NO, then why trying to modify what is working.

If the abswer is YES, are you shure a change in ph will solve the issue (s).

Every time I tryied to modify something, without an issue in my tank, I screwed it and lost tons of corals. Last time it did happen to me was last January. Since then I have been trying to recover stability in my tank. And since then I have sworn to all the Gods in this planet that I will never modify anything unless there is a real problem.

Cheers
Daniel

 

[nemodan]

One more comment.

I had in my APEX the standard probe and the ph swing was between ~7.8 to ~ 8.45 - 8.6

Changed to the lab grade probe and the reading changed immediately to what i posted previously.

Do you have a good ph probe/kit to measure the ph value with precision ?

Cheers

 

[cilyjr]

A standard pinpoint probe.. Maybe 1 lab grade might be worth it...do they last any longer?

It's all controlled with an apex

 

[cilyjr]

well I had an extra larger diameter vinyl hose that would reach outside so i hooked it up. i guess we will wait to see if that helps raise ph. I will need to keep an eye on skimmer performance because restricting the air lessens it.

 

[bill120mph]

I removed my reactor , and started again practicing life without it, I found that although I was getting the results i expected I was loosing ph, I reintroduced it slowly with less co2 over a longer period and had better results, I thought I had it dialed in, but was only looking at alk and cal as I first did it. In My Opinion a reactor must be dialed in over a month or so period of time.

 

[wpeterson]

Sorry to revive a month old thread, but I just had a conversation with a new member named Mark at the last meetup around pH levels and diurnal swings.

First of all, the advice of folks not to chase pH unless it's wildly out of range (<7.8, > 8.5) is the most important thing. If your pH is out of range and your controller/probe are old or have been dried out, I'd re-calibrate the probe before I sweated a reading.

If you do think you've got a good reason to level out pH, using a reverse-lit refugium is the safest way to do it and something I've had good luck with. The ability to have an impact here is all about the relative size of photosynthetic organisms in your refugium vs. your display tank. I've had good luck with dense chaetomorpha macroalgae in the refugium for nutrient export and also to balance pH swings when the refugium is brightly lit at night.

You should see two pH curves for photosynthesis pulling CO2 out of the water, raising pH until it tops out at the metabolic capacity of the biomass, once for the refugium and once for the display. You can change the offset in your light cycles until those two curves overlap and slightly cancel eachother out into one less extreme curve for the diurnal cycle.

 

[mind]

There is a BRS video where they added a CO2 absorbant (called divesorb/sodalime/etc) into a reactor and pulled air through it before it entered the skimmer. This removed the CO2 in the air (higher at night). Since the sodalime is expended during this process (and costs money to replace), they put a APEX controlled solinoid into the line to only pull air through the sodalime reactor when the pH was low.

Incidently, the scuba diver community uses sodalime for rebreathers. It comes in a 'indicator' variety as well which will color change when expended. It can be ordered in bulk (I have ordered pallets of containers before). For best results, run two reactors in series and when refilling one, swap the other's position.