Alk/DKH to high, and why?

[Pro_builder]

Boomer,
I have a situation that you could help me figure out if you have time... I understand if you don't.

I have a Alk/DKH: 16+ Salifert test kit (2 different kits)
pH: 8.19 AM 8.24 PM (Octopuss 3000 lab grade probe calibrated & new)
Ca: 430 Salifert
SG: 1.026 Refractometer ATC
Am: 0 Salifert
Nitrite: 0 Salifert
Nitrate: undetectable Slifert
Mg: 1325
Temp 79.5 to 80.2 Octopuss
Orp: 385 AM to 426 PM
I have no Ca percipitation in the tank.

1: What should I do to lower the ALK/DKH or do I need to worry about it?

180 gallon tank, 6" DSB, 180 lbs LR, refuge (lighted 24/7), skimmer for 600 gallon tank, dripping Kalk in PM, 5% water changes every week, 3-250 watt MH 15K XM's, 380 watts VHO Actinics.

[Boomer]

Only two things Troy.

1. Have some else check the dKH with a different kit to be SURE. If it is still high just leave it and not add any buffers or Kalk, letting it come down on its own. Just monitor the ALk, Ca++ and pH each day. I think your Alk demands are low and the Kalk is bumping it up to much. This is often common with kalk at times. Your pH seems to show a slight CO2 problem but it is not to bad. Find a way to aerate or get better gas exchange at least at night. If can do it will make #2 better for you.

2. For starts cut the kalk concentration in-half and keep the PM drip and see where it goes. This should drop the Alk and the Ca++ to lower levels and hopefully the pH will remain the same or not drop below 8.00 at night. We are looking for a Alk no higher than 11.2, pH min 8.00 at night and Ca++ can go to 390. This kalk concentration fine-tuning is trial and error. If the Ca++ drops to 410 by cuting back the kalk the Alk should drop to at least 13.2 but the buffering needed should drop it maybe 13. If the Ca++ dropped to 400 the Alk would be 11.5 ( OK at max Alk) and 390 to 10.2. 390 is more than enough Ca++ for even sps. All they need is 360 really. So getting the Alk and Ca++ down is not an issue but what will be the issue is the final pH we get doing this, which we do not want below 8 at night.


I do not believe you need to do a water change yet, unless things get out of hand. If you did a water change you just may end up with the same problem next month. We need to see what is going on and why.

[Pro_builder]

Thanks Boomer,
The reason that I have been dripping Kalk is to keep the pH above 8 at night. I am not dripping much to achieve this, about 1 drop every 2 seconds, then I still have the RO/DI water for top off. As you said my CA++ demands are low right now.
I have had the tank water tested by the LFS 2 different times and his reading are the same as mine. That was the first thing that I did was make sure that my testings were right. I even recalibrated the pH and Orp probes 2 separate times. The reads never even budged from the originals after reclaibration.

Now what is the best way to keep my pH up at night if it starts to drop again at night with out dripping Kalk? I am asking just so we don't mess up the test to find out what is going on. Or is that why you are telling me to drip half strength kalk?

Thanks again for the chemistry input. You are a genus!!!

[Pro_builder]

So are you saying that my Co2 is high or low?
I have a lot of bubbles in my sump since it is in the basement. I am running 2- 1 1/2" overflows into 1- 2" pvc pipe to the basement sump. It runs over a baffle then back up to the tank through 1- 1 1/2" return pvc that splits into 4- 1" return lines. 1 in each corner and 2 that plumb together from the overflows to a spray bar along the back of the center tank. With holes pointing down the back glass, and forward towards the front glass.
Should I drill some holes that point towards the water surface to aggitate that too?

[Boomer]

You CO2 is slightly high. If we can get rid of some of that the pH will go up. If the pH goes up we can cut back on the kalk, lowering the Alk and Ca++.

Now what is the best way to keep my pH up at night if it starts to drop again at night with out dripping Kalk?

Only gas exchange or find out what is causing the low ph, which is the plants resting and we can not stop that. Another thing you could do to counter this is get a refugium and put it on reverse lighting. These plants will pick-up the CO2 at night from the tank and rasie the pH.

Should I drill some holes that point towards the water surface to aggitate that too?

That may help but think refugium. I don't know why I left out a refugium it should have been #3. For now cut back on the kalk by 1/2 and see what you get. You can always bring it back up

[Pro_builder]

I have a 75 gallon Refugium on this setup. The algae isn't in abundance but growing fast. It is calupra, I think. Has small grape like bubbles all over hte stems. The lighting is on 24/7, so it won't go sexual????????
That is why I don't understand the pH dropping so much at night, and the Co2 so high.

[Boomer]

Yah sound like grape caluepra Troy

The CO2 has to come from somewhere. More than likely slightly high room air CO2. Plants don't like 24/7 and do not do well. 24/7 is a myth. Switch to night only and maybe get some Cheato.

Troy a drop of only .05 pH units is almost none at all/say. Many have tanks that drop more than that, like .1 or .15 units pH or even .20 units. However, if you shut off the Kalk drip at night doing all the correcting at night it would be higher (CO2) for sure and the pH lower. But you still have very good control of it 8.19 night and 8.24 day = .05 offset. That is better than most by far. Your only real issue as I see it is that high Alk. Maybe you need to go to a two-part

How to Select a Calcium and Alkalinity Supplementation Scheme
http://www.advancedaquarist.com/issues/feb2003/chem.htm

[Pro_builder]

Ok, I will switch the Refuge lighting to PM only. I still haven't done any Kalk dripping. My pH this morning was 8.3, Alk 14.75, Temp 80.2 And no water change this weekend.
One thought that I had..... .....ooppss broke the bulb!!
I washed out the Rubbermaid Stock tank (100 gallon) that I am using for a sump, with Vinegar, could it have soaked up some of the vinegar and now be slowly releasing it into the water? My thought is that vinegar will drop the pH (faster) and Alk (slower) but the Alk will have a tendency to rise significantly after the lowering affect of the vinegar........
..... Could this be a possibility???????? You are the master.

[Pro_builder]

I like the Kalkwasser way of replentishing the Calcium and Alk to the tank. It is simple and I really don't think I will have a SPS (Heavy load) tank that will need a CA++ reactor. Atleast not yet. Since the wife likes the softies too. But, we will have some LPS's in the tank, like a brain or 2, moon's and maybe a monti cap or 2. Nothing really major though.
I will check my pH, Ca++, and Alk about 30 min. after the lights come on to see were I am at, at that point today.
Thanks for all your help and insight in this matter.

[Boomer]

Nah, I dont' buy the vinegar thing. Yah, kalk is a good thing/best thing most of the time.

pH 8.3 AM dKH 14.75

[Pro_builder]

Here is an update on the tank stats:
1:00 pm Lights just truned on:
pH 8.22
Alk 16
Ca++ 420
temp 80.2

6:20 PM lights on for 5 1/2 hours:
pH 8.24
Alk 16
Ca++ 415
Temp 80.75

Thanks on the reply on Vinegar idea, I thought it was a long shot but it was something that I did out of the ordinary from other tanks. So, thought it was worth mentioning, so you had all info involved.

Switching the lighting scheme on the Refuge to PM only has helped stablize the pH.

Is there a way or additive that can be used to drop the Alk?

[Pro_builder]

Or am I concerned about nothing?

[Boomer]

Is there a way or additive that can be used to drop the Alk?

Yes there is but I'm not going to TELL you what it is It is very nasty stuff and to much to go wrong.

[Pro_builder]

Enough said on that subject then. But, I would still like to know, just for the knowledge

[Boomer]

HCl/ Muriatic Acid but it also hits pH