Issue dosing Kalkwasser

Jman72

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Hello all, I've setup my first saltwater tank and I'm getting ready to buy my first few coral frags but I'm having 1 issue. I've just recently started putting kalkwasser in my ATO and I've been having ph swings which I'm not sure if they are acceptable or not. I went from 7.9 to 8.15 ph in a 24hr period. But the real issue which confused me is that it peaked at 8.15 and then dropped back down to 7.9 in about 12 hours. I'm running the Apex Dos for my ATO and it was dosing the entire time that it went from 7.9 to 8.15 and back to 7.9 from the same batch of ATO. So I'm not sure if I'm dosing the right amount or dosing too fast. My tank is going to be for strictly SPS coral so I'm trying to get everything as stable as possible before I put anything in the tank. I have about 30 gallons total of water. Here are my current parameters:

temp: 78
salt: 35.6ppm
Ph: 8.0
Alk: 7.7
Ca:430
Mg:1400
 

Retro Reefer

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IMO dosing Kalkwasser via ATO is not a good idea.. the amount dosed will vary with your evaporation rates which is constantly changing, calcium hydroxide will also clog and degrade the performance of your ATO pump over time. I drip my kalkwasser or you can use a dosing pump.. I wouldn’t chase PH numbers just focus on keeping your calcium and alkalinity in line

BTW.. Welcome to R2R!
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mcarroll

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Watching pH less closely will help more than anything. :) ;) Those numbers aren't going to bother anyone.

Retro is right that you have to be pretty careful with kalk. It might not be the best tool to use at the beginning when your doses are small and hard to measure in the first place and when the product can "decay" in your ATO reservoir due to nothing more than atmospheric interference. Manually-dosed two-part might be better.

That said, if you're worried specifically about a pH spike yet still want to work with kalk, then combine your kalk with vinegar. This changes the kalk and neutralizes pH. (see: http://www.reefscapes.net/articles/breefcase/kalkwasser.html)
 
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Jman72

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ok. I've already read hundreds of times not to chase ph which I understand, so that ph swing wont bother SPS?
 

chipmunkofdoom2

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ok. I've already read hundreds of times not to chase ph which I understand, so that ph swing wont bother SPS?

The magnitude and the rate of change matter a lot. If that change was in a few minutes, it would probably be a problem. If it's over the course of a day, it's not a problem, and is likely normal.

It's pretty common for tanks to experience a daily pH swing. While the lights are on, organisms are photosynthesizing and reducing the CO2 concentration in the tank, which increases pH. When the lights turn off, organisms stop photosynthesizing, and CO2 can begin to accumulate again. As the CO2 goes up, the pH goes down. When the lights turn back on, the cycle repeats. So you have sort of a day/night up and down cycle. This may have nothing to do with dosing calcium hydroxide.

Although, as said by a previous poster, I personally would not dose anything in my ATO. I am not comfortable with the lack of accuracy and lack of control of dose that comes with almost all ATOs.
 

mcarroll

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Personally for dosing..
...I started with water changes
...then moved to an all-in-one
...then to two-part
...then to two-part+kalk/vinegar

That was all dosing by hand, manually.

Once I got a doser (after about 7 years) I went to 100% two-part.

$0.02 :)
 
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Jman72

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Ok, I've now setup my kalk to slow drip from a 1 gallon ATO container and adjusted the dose. I've managed to stabilize my ph within the 8.1-8.2 range. However, I'm dosing 1.5 tsp of kalk per gallon for my 30 gallon tank (sump included) and I'm dosing about 3 quarts every 24hrs. This seems like a high dose to me considering that my tank is empty. Is this normal?
 

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Ok, I've now setup my kalk to slow drip from a 1 gallon ATO container and adjusted the dose. I've managed to stabilize my ph within the 8.1-8.2 range. However, I'm dosing 1.5 tsp of kalk per gallon for my 30 gallon tank (sump included) and I'm dosing about 3 quarts every 24hrs. This seems like a high dose to me considering that my tank is empty. Is this normal?
Are you maintaining stable alk with this rate?
 

chipmunkofdoom2

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Ok, I've now setup my kalk to slow drip from a 1 gallon ATO container and adjusted the dose. I've managed to stabilize my ph within the 8.1-8.2 range. However, I'm dosing 1.5 tsp of kalk per gallon for my 30 gallon tank (sump included) and I'm dosing about 3 quarts every 24hrs. This seems like a high dose to me considering that my tank is empty. Is this normal?

This is a little confusing. Do you mean you put 1.5 tsp of calcium hydroxide into the 1 gallon dripper? And that you drip 3 quarts of this solution in a 24 hour period?
 

chipmunkofdoom2

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That's a lot, more from an evaporation standpoint than anything else. You're evaporating almost 0.75 gallons of water per day. The dose of alkalinity and calcium is a bit high too. At 1.5 tsp per gallon and 3/4 gallons dosed per day, a 30 gallon tank receives a 2 dKh boost and 15 ppm of calcium from that much limewater.

Brew's question is valid, is your alkalinity stable?

EDIT: re-read your post, how much two part are you dosing? This sounds like your tank is consuming a lot of alkalinity and calcium, especially if nothing is in it.
 
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Jman72

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I'm dosing 300ml a day of 2 part. The mixture is 2 grams of alk per 1 quart and the same for calcium.
 
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Jman72

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After thinking some more about this, I'm kind of wondering if this could be a CO2 issue, because if I stop dosing Kalk altogether, my PH continues to drop pretty quickly. It has dropped below 7.8 after 2 days of no kalk and will probably continue to drop. I haven't let it frall further than that but it wasn't showing any signs of bottoming out. My other parameter still remained fairly constant which is what puzzles me. I do have a 1/4in airline running from my window to my skimmer, but I don't really think its doing much because the skimmer is fairly small. I've also put in a tank with an airstone after my RO filter and before my DI filter so I can prolong the life of my DI resin because I was burning through it pretty quickly and concluded that it was from high CO2 in the water.
 

Brew12

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After thinking some more about this, I'm kind of wondering if this could be a CO2 issue, because if I stop dosing Kalk altogether, my PH continues to drop pretty quickly. It has dropped below 7.8 after 2 days of no kalk and will probably continue to drop. I haven't let it frall further than that but it wasn't showing any signs of bottoming out. My other parameter still remained fairly constant which is what puzzles me. I do have a 1/4in airline running from my window to my skimmer, but I don't really think its doing much because the skimmer is fairly small. I've also put in a tank with an airstone after my RO filter and before my DI filter so I can prolong the life of my DI resin because I was burning through it pretty quickly and concluded that it was from high CO2 in the water.
Low pH is always a CO2 issue. You are absolutely correct in that thinking. Have you considered running an air stone in your sump with the feed taken from the open window?
 
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Jman72

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I did have an airstone in the sump for about a day with no effect, but I haven't tried with the intake coming from outside because the intake is just a hole with no fitting that I can attach a hose to. I guess I can put the whole pump in the window, but thats not a good long term solution considering that if it starts raining outside my pump will get fried.
 

mr9iron

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Have you tried some different test kits and compared the results. For a tank with nothing in it you sure are adding quite a bit of alkalinity and calcium. That leads me to believe your test kit may be faulty.
 
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