magnesium is not measured in any of the alkalinity tests nor is calcium so dosing with either isn't going to give you a higher pH

magnesium simply helps you maintain higher concentrations of calcium. I can't remember reading anywhere that corals or fish are affected by high or low or fluctuations in magnesium.

how is your pH---if low you could use kent reef boost--it will raise the alkalinity and the pH (I think it is due to the boron in it)
fluctuations in pH and alkalinity could affect the health of inverts.

I do use a Salifert Magnesium test kit. I also run a Kalk reactor on both systems and drip with top-off water 24/7. The reactors stir the Kalk 4 times a day for 15 minutes at a time. I have a basement fishroom and my PH remains in the range of 7.8 to 8.0 as the A/C running all summer has an effect on it's level. In the fall and winter its more in the 8.2 range as I have a vent that's open for fresh air in the room.

First you need to understand that the test kits we use are not 100% accurate. A kit that costs under $50 is pretty good but I think that real labs use stuff that cost 10x what we pay. but mostly stable to me means that it is around the same. You should also get in the habit of testing around the same time. So if you test every day you should do it at the same time of day.

If had to give some +/- I would say

Alk +/- 0.5
Ca +/- 20
Mg +/- 30

Here are my records for about 1 1/2 years of taking monthly readings.


I started keeping my alk lower and Ca higher in Dec 2003. The spike in sept 2004 is from being lazy for the summer. But no problems happened because of it.

Thanks. When I said I had a 10pt swing on readings, stupid of me, I forgot a decimal. I'm no chemist; I also prove I'm no mathematician.

FWIW, your MG levels can drop somewhat faster in your system if you use alot of kalkwasser/lime. Just thought I would add that.

Thanks, I did not know that was the case!

very helpful--thanks
I am not clear on the symantics here-----I gather you are receiving accurate results monthly---but how often are you testing and dosing---I am using the same dosing chemcals as you stated you are using---once a week.
I have a reefing buddy--who uses the two part system and doses everynight --I was just tank sitting for the last week--he has two plastic cups with the lines marked on it for daily using and I think he monitors it once a week. personally I prefer to test and then dose----so to state a clear question to you:
If ph alk ca and mg are stable----do they remain stable for the week (taking into consideration that the two tanks I mentioned above are 10 and 8 months old)

I am trying to grasp the chemistry here--I thought magnesium simple bonded with calcium so you could supersaturated calcium levels. I was under the impression that it was not used up in this process---and as a result ---once you got the magnesium levels up to 1300 or so then that level remained very stable.

I test once a month. In the beginning I tested more often but for the last few years of the tank I only tested once a month. If something was really off I might test it 48 hours later to see if things got back on track.

I dose ca/alk through a ca reactor and kalk reactor so that is done all the time. The Ca reactor is on 24/7 and all top off water goes through the kalk reactor. Mg is only added to water change water. I do that once a week.

very similar situation----is 7.8 the lowest it goes or is the kalk reactor set at this point. the reason I am asking because mine will drop over a week from 8.1 to 7.7---at that point I either use calcium hydroxide or buffers depending on the alkalinity level.
If I left it alone would it continue to fall or would introducing something so basic as opening the basement windows and or using an air stone help?

thanks I understand that--but in my situation where I have to dose by hand--would the water parameters be stable for weekly testing or should it be done everyother day etc?

Well only indirectly.

http://www.reefcentral.com/forums/sh...t=kalk+and+mag

Once you have things so you are dosing the right amount. I don't think you should need to test more than once a week.

I don't run the Kalk reactors on a shut off/probe system at all. If it starts to dip lower than the 7.8, I know it's time to refill the Kalk/lime media and then the PH rises back up.

ok then--you are doing the same thing as me-- have you ever observed it following below 7.8

This is the problem in understanding I am having---if pH is lowering because of carbon dioxide conditions in the house then there should be a point where the carbon dioxide levels off in the house and concurrently in the tank so if you ignore the following co2 rate like some suggest it will start to come back up on its own.

Yes, I have hit in the 7.7's and then added Lime to the reactor. The interesting thing is that I have 2 sump/fuge systems side by side in my fishroom and one has lower PH than the other. The one with the lower PH has the display tank located in the basement, so that's what I concluded to it having low PH with the Furnace in the basement... or a different Kalk Reactor not working as well as the other. The system with the higher PH, the tank is on the first floor. Also, both sump/fuge systems are in the basement as well in a 10x21 fishroom.

Rather than repeat what I've been told without quite understanding why it should be, I asked in the Reef Chemistry forum about these statements: 1. Dripping kalk may cause phosphate to precip out, and putting it right over your skimmer intake might help you bail some out; [generally good for corals] and 2. dripping kalk may cause mg to precip out. [can be a fixable problem for maintaining alk/cal.]

The initial respondent says yes, to a minor degree. The thread link is:
http://www.reefcentral.com/forums/sh...readid=1181767

Bertoni replied NO to the same question about Mag when I asked it after reading it in Randy's article.

Well fiddlesticks.....Randy agrees with me because I see it HAPPEN IN MY SYSTEM.

I will admit I read most of this but not all so forgive me if this is in here. I've always tried to keep my alk at 10ish Dkh.....I find that everything does much better. I prefer to have my calcium on the low end. When my Alk got below 9 my Trach brain would not open during the day (not SPS I know). Since then I have tried to maintain my alk at a higher level.....also seems to keep any algae down (maybe the higher more stable Ph?). I JUST as of yesterday added a Kalk reactor so hopefully that will level everything out? I am sort of new to SPS but have never lost one......probably over 9 months or so....I have never seen RTN or STN. Just wanted to add my 2 cents.....also I have never tried higher calcium and lower alk for any period of time.

I don't think it is simply location of the furnace------
not all lowering of pH is strickly due to carbon dioxide levels in the tank. Also I think carbon dioxide problems in the house are a combination of air circulation and insulation. ---and carbon dioxide/ oxygen exchange occurs on the surface of the water of the tank besides in the sump/refugium and skimmer.
----and the hotter the room the more carbon dioxide it can hold

my eg here
--my sump and fuge are in the basement also--the main tank is in a small room at the front of the house. If I close the door to that room the circulation slows down and the temp really rises quickly due to the sun coming in the windows and the halides over the tank. You walk into that room after 15 min and it is very hot and the air is stiffling. Yet the air in the basement where the air conditioning is drawing from is cool and not hard to breathe---my pH in the main tank fluctuates over the entire week from 8.2-7.7.

I have a 30 gal quarantine/frag/reef tank(depending on the crisis) right beside my fuge and sump in the basement. The pH never ever moves---8.1 steady.

Yes, the air is warm in the room during the summer as I shut off the incoming air vent from the outside that was installed. Illinois is hot and humid in the summer. I keep the door open just a crack, but it does not help the heat factor. My husband is into collectibles and if I dare rust his collections in the basement, I'm in BIG trouble. PH stays in the 8.1 to the high 8.2's when the air is not running and the outside vent is opened (spring, fall & winter)

Since there seems to be some talk on this thread regarding ph I have a question.

How in the heck do you guys with a kalk reactor keep it stable?. I dose all top off with it at a drip rate and ph really fluctuates depending on how much kalkwasser I have in the reactor. Seems to keep it stable I'd have to add a certain amount every couple of days. If I add say a cup a month the ph swing from when it's added to when it's about 1/4 left is pretty dramatic (around 8.0 - 8.5).

thanks,
Albert

Bertoni came up with an interesting observation: if you are supplementing [an dI hope I'm quoting him right] with 2-part or Kent's or whatever, you're actually adding some mg.

If you are supplementing with kalk, you are not, because there is no mg in kalk.

So if the corals are using mg, and you are not supplying it via your supplement, the net effect is that you are losing mg and need to supplement more.

That may reconcile Randy with Bertoni. Bertoni makes those comments in the thread I linked to above.

is there a diagram anywhere showing the propper setup for a kalk reactor?