Kalk & Vinegar Question

[Randy Holmes-Farley Verified Community Expert]

I've been using kalk for 20 odd years. Recently stopped because my pump bust, just compensated with bicarb and calcium. Yet to notice any difference tbh.

It’s always good to hear changes or not from such “experiments”. I never bothered to test the effect of my old skimmer on aeration until the pump had an issue. lol

 

[Randy Holmes-Farley Verified Community Expert]

Sounds like you have this all figured out.

I'm curious where the 2tsp of Kalk/per gallons came from. I thought max saturation required closer to 4.75 tsp of Kalk mixed into a gallon of RO/DI water?

I do use a dosing pump to dose Kalk in addition to dosing Part A and B. I bias my dosing so I dose the A and B at a slightly higher rate during the day when PH goes up and then dose the Kalk at a slightly higher rate over night to keep PH from dropping as much. I find dosing Kalk hourly, and A and B as well not only gives me better control of the PH, but also helps me smooth out the ALK swing.

Saturation at 25 deg c is exactly 0.0204 M or about 1.5 g/L. With most powder calcium hydroxide, that translates to about 2 teaspoons per gallon of ro/di.

 

[Ultraman]

That's supposed to be the low point of pH for the day, so being low isn't that surprising.

How accurate is your pH reading? Do you have a way to validate your number, such as a second type of test?

Often there is a factor like +/- 0.2 pH units on a given meaurement.

If your reading is indicating an actual pH of 7.7 in the morning, then IMO this is not really an issue.....mostly a reflection of CO2 buildup, which is not going to be an issue for corals at this rate.

If your pH meter also happens to need a calibration then the factor can be off by even more of course.

IMO this is just not an issue. That just seems to be the assumption at the start of the thread.

That said, if you really want to raise the tank's pH range then do just about anything to improve ventilation to the fish room, sump room or whatever houses your setup. (What you're doing is very temporary.)

If you haven't done Randy's pH test to see if its the aeration of your tank or the air in the room that's dictating your pH, do that next. 9/10 times it's just a local ventilation issue.

Doing something in that area will trend up your pH levels, but I still wouldn't count on this strategy for coral fixes. CO2 is a fertilizer to them. So unless something else is missing (eg. N or P, etc), there's no reason additional CO2 should be viewed as other than a nutrient.

Have you had any other threads where you tried yo dig into the SPS issue?

I'm not sure what tank it was for, but I did notice in some threads you mentioned chemical treatments for algae. "Rough looking" SPS is the minimum I'd expect from those treatments (along with algae regrowth once you water change the chemical out of the water). Sometimes corals never quite recover their original color and brightness after that.

Sorry for not replying this week, got busy and forgot about it. I appreciate your reply and experience. I do have very good air exchange with a 6” vent on one side of the room and a 6” vent with a 400CFM fan going 24/7. But, I’ve not done Randy’s test in a few years but when I did it wasn’t different after aeration.

My friends all swear by Kalkwasser dosing and their results are very good with sps. I finally figured a place for a 29 gallon tank and made it happen with help from a friend. My pH is still staying in the 7.6/7.7-8.0 range. My five year old probes were replaced with new ones and calibrated spot on with no adjustments necessary on the new ones. Same readings on the new ones versus the 5 year old probes.

My SPS have been doing decent, but I have some caulerpa that broke loose and got in some colonies killing them off from deep inside. My fox face rabbits are making it disappear slowly.

I’m trying to back off on my bubbles per minute on the calcium reactor with the aid of the Kalkwasser. pH from the calcium reactor is now 7.0 instead of 6.8. Alkalinity is 8.1-8.3.

I think I’m done chasing numbers now and will see what effect the Kalkwasser dosing does over the next few months. Subjectively, the acropora look healthier and I’m seeing some growth on several that haven’t done much the last couple of years. I typically use 4 pounds of GFO a month on this tank to keep phosphate somewhat controlled. Kalkwasser might help precipitate phosphate and maybe I can save some money there.

 

[mcarroll]

I do have very good air exchange with a 6” vent on one side of the room and a 6” vent with a 400CFM fan going 24/7.

...vents from your HVAC, or are you saying vents bringing in outside air?

If the answer is outside air, then your tank is practically an outdoor tank… Seems like that would be a challenge to heat/cool.

If the answer is indoor air, then I would still be curious to see the results from a inexpensive CO2 monitor.

Does it make sense that you think you have a pH problem but Randy's aeration test showed nothing? ...maybe I am overthinking now, but that seems confusing to me.

I typically use 4 pounds of GFO a month on this tank to keep phosphate somewhat controlled

There are plenty of folks out there growing banging SPS tanks… Even spawning them…at super high nutrient levels. I would absolutely experiment with backing off GFO by at least -1 pound per month. But I would do nothing to compensate for it… No carbon dosing… No extra water changes… No change in the feeding program unless you are broadcast feeding in which case I would squelch that as well. We want maximal feeding rates, but we do not want food wasting.

The only change I would expect to see if you tried that would be increased growth and color. So maybe you would have a little bit more work fragging.

I wonder if at least part of the originally stated problem with your SPS growth has been that nutrient levels could have been higher / over use of GFO? (I would've flagged the GFO in the opening post if there was any reason for the info to be there.)

Still add kalk dosing if you want... but if I were in your shoes, I would be experimenting with less GFO... maybe even zero.

600 gallons worth of hard coral represents a ton of phosphate demand… I would not necessarily throw any limits on it personally.

 

[Ultraman]

I’ve got a 6” vent to the outside on one wall and a 6” vent to the outside on the other wall with a Panasonic fan blowing air out 24/7. It’s not outdoor air but it’s definitely well ventilated.

I’ve always kept PO4 0.1 to 0.3 with gfo and figured higher PO4 would limit growth. I also have a sulfur denitrator that’s starting to dial in after a few months of finickiness. My nitrate is close to 40 and phosphate is .10-.30 with the gfo. My denitrator running well usually keeps NO3 around 20.

I could cut back a bit on gfo and see if growth improves. My ph is 7.7-8.1 today. Most people struggle with no N &P and I struggle with too much.

 

[mcarroll]

I’ve got a 6” vent to the outside on one wall and a 6” vent to the outside on the other wall with a Panasonic fan blowing air out 24/7. It’s not outdoor air but it’s definitely well ventilated.

Sounds like it!

I’ve always kept PO4 0.1 to 0.3 with gfo and figured higher PO4 would limit growth.

.1-.3 isn't too bad (you don't mean .01-.03, right?) but higher shouldn't hurt anything and does have the potential to help, including growth.

I also have a sulfur denitrator that’s starting to dial in after a few months of finickiness. My nitrate is close to 40 and phosphate is .10-.30 with the gfo. My denitrator running well usually keeps NO3 around 20.

Seems like that should continue to be a good range even if PO4 drifts higher.

I could cut back a bit on gfo and see if growth improves. My ph is 7.7-8.1 today. Most people struggle with no N &P and I struggle with too much.

Many a sweet reef runs in that pH range.

I'm guessing you have a pretty intensive feeding routine, so I bet there's a ton of N&P going into the tank every day. (Which is excellent as long as the fish are eating it all....and "leaving" the overages for your corals. )