Alkalinity questions

[Shirtlessbill]

Hey all,


I've got a 75 gallon tank that has been up for about 7 months now and I've been struggling to keep alk my stable. (Ill include pictures of my charts) it seems to "peak" at about 9. What can I do to help this. I add Brightwell Aquatics kh buffer as recommended every other day (sometimes two days in between) for the last moth. And was under the impression that I wanted to get my alk to about 10.

My tank seems very healthy. I'm seeing natural propagation from multiple corals (sacrophyton, Xenia, ricordias, galaxea, branching hammers, and crown leather) and also seem to have an explosion of coraline over the last few months.

I'm hoping to get to a point where I don't need to dose every other day. Will this happen eventually or is this just part of the hobby? Also, what factors dictate my alk levels?

I know this is a loaded thread so thanks for any/all help

 

[MaiTank]

Do you use RO/DI water?

 

[Shirtlessbill]

Do you use RO/DI water?

Yes, I have a BRS 4 stage RODI unit with TDS meter

 

[Dimdim]

Ro di water is very soft. That could be the reason for alkalinity dropping, also depends what salt mix your using with ro do water, im using reef crystals and noticeds its dkh at 79degrees is a steady 9.5 or 10. Ive dropped from 12-13 dkh to 10 after switching to reef crystals, regular pwcs will help keep it up too

 

[ccCapt]

You don't really have much in the way of corals that will consume alot of alkalinity. Alk is used when corals form their hard skeleton. It's also used when coralline algae grows, so that may be what's using it. If you are seeing a drop in alkalinity, you should also be seeing a drop in calcium and to a lesser extent magnesium. When corals grow their skeletons or coralline algae grows, they use a defined amount of alk, calcium and magnesium in that process. For every aprox 2.7dKH of alk "lost", you should also see a drop of about 18ppm calcium and 2 ppm magnesium. Do you also test calcium and magnesium? Depending on how often you do water changes and which salt you use (some are very high in calcium) you may not notice the calcium dropping, but it is none the less.

Natural seawater is around 7dKH alkalinity. I keep mine between 8-9 dKH. As long as you stay in the 7-10 dKH range you are fine.

 

[Dimdim]

You don't really have much in the way of corals that will consume alot of alkalinity. Alk is used when corals form their hard skeleton. It's also used when coralline algae grows, so that may be what's using it. If you are seeing a drop in alkalinity, you should also be seeing a drop in calcium and to a lesser extent magnesium. When corals grow their skeletons or coralline algae grows, they use a defined amount of alk, calcium and magnesium in that process. For every aprox 2.7dKH of alk "lost", you should also see a drop of about 18ppm calcium and 2 ppm magnesium. Do you also test calcium and magnesium? Depending on how often you do water changes and which salt you use (some are very high in calcium) you may not notice the calcium dropping, but it is none the less.

Natural seawater is around 7dKH alkalinity. I keep mine between 8-9 dKH. As long as you stay in the 7-10 dKH range you are fine.

+1 any reef with alot of lps or sps will suffer these drops in levels. I have a few lps, and alot of new coraline growth, dang coraline! Lol

 

[uh.oh...]

I'd look into getting a dosing system going. Either with an aqualifter or maybe the brs, do you already have a controller? Super easy once you get it set up

 

[Shirtlessbill]

I use aqua vitro's Salinity mix for reefs. I do a 5 gallon water change every other week (10 of 75 gallons a month) As far as I can tell I don't know why my calcium and alkalinity drop. Most of my corals are softies (Xenia, crown leather, zoa colonies, etc) with my only stonies being branching hammer, Galaxea, and a small frag of sps. Can coralline algae really effect my tank that much? I thought regular water changes would keep a tank going until the colonies matured; maybe I'm wrong.

Thanks for the ideas.

 

[Dimdim]

Your water changes arent enough to keep with ur livestock using up the calcium and alk. Do one 5 gallon change every week. I do a 4 gallon change on my 40 gallon every week and i still get low reading the day or two before water change day

 

[deepseadan]

Are you adding calcium to or just alk increaser?

 

[Sniperhank]

I'm not really seeing a problem with the levels. The peak is obviously from you dosing the tank to raise the alkalinity, but then goes back down to normal. I fought with my tank and the alk levels being, what I thought to be low. Dosed and could never get it to stay up. I just had it stuck in my head that I had to get it up. My reef was fine before and was fine after...but messing with the alk levels sure made some things angry. If it works, don't fix it.

 

[Shirtlessbill]

I'm adding both alk and calcium buffers.


I'm fine if it doesn't need to be at 10. I thought I heard somewhere that 10 was a good number to hit. My bigger concern was that my calcium levels had dropped so low. About a month and a half ago I tested my calc levels at 330. Obviously very low. It just seemed to come out of no where and at that point my alk was 7.9.

What I want is to get my tank to a point where my calcium doesn't swing. I feel like my tank is too young as far as corals go to be consuming that much but maybe I'm over thinking it

 

[Sniperhank]

I'm in agreement with your tank being pretty lightly stocked in corals to be seeing such drastic swings. I would say your alk is low for the same reason mine is...if you figure it out let me know! Lol...
What I would do, test your alk and calcium right after you mix up your water. That will give you your baseline. It is just hard to believe all your stuff is being absorbed when there isn't that much in there to consume it. My calcium stays steady at 595 and my kh is always at 80 (breaks down to about 5 or 6 I think if the math is right), but this is with Kent salt mix. My point is that if it is stable and you have corals growing, then just let it go. Our fiddling with it can cause an issue, when there might not have been one to begin with. My test results are from Hanna checkers.

 

[deepseadan]

If you're dosing both alk increaser and calcium that often on such a lightly stocked tank I would check your magnesium. I would bet you're low. Magnesium is a interesting element in the reef. It's not that it is important because your corals use it directly (they do use a tiny amount though), but because it asks a separator agent to keep calcium and carbonate from bonding and precipitating out. Watch this video in the link, it explains it much better than I can. http://youtu.be/mI52IyBtjp0