[quote author=GreshamH link=topic=3137.msg34615#msg34615 date=1203637306]Kalk still won't give a "spike" what hobbyists know Alk as being. Of course PH relates, but not in terms of this discussion as you can boost your PH to 12 with KALK and it wouldn't reflect in your current total ALK when measured using normal hobbyist methods before or after the dose.[/quote]
Ok, for the sake of demonstration, I went ahead and simulated a couple of fast kalk additions and measured alk to get some sample readings.
The premise is that someone quickly doses ~4 liters of saturated kalk water to a tank with 75 gallons total system volume.
(4 liters X 1000ml/liter)/(75 gallons)/(16 cups/gallon)=3.3 ml/cup
So to make things easy, I figured 4ml of kalk water to 1 cup of tank water would be a reasonable approximation.
I took an 8oz sample of tank water and tested the starting alk using the API reagent with my high precision syringe method.
Next I dosed 1ml of saturated kalk water to the 8oz sample to simulate adding 1/4 of a days worth of top off very quickly. I stirred the sample then measured again using the modified API method.
After that, I added 3ml of saturated kalk to the sample, mixed well, and did a third alk test.
Results as follows:
tank water + 0 ml total kalk addition : 3.21 meq/L
tank water + 1 ml total kalk addition : 3.39 meq/L
tank water + 4 ml total kalk addition : 3.85 meq/L
So that pretty much shows that fast kalk additions cause jumps in alk levels.
What can make things worse is if you "dose lime water twice a week ( 5 gallons drip in)", and you don't dose slowly and continuously over the week to match alk consumption and keep your alk stable...
i.e. you dose quickly so that there are some days during the week where you don't drip kalk...
Your clams and corals will suck your alk down low on the non drip days. Then you bump it back up with the next batch that you drip. And that's on top of the pH swings from the nondosing/fastdosing procedure.
Using the above numbers as an example....
Let's say that your system uses 3.85-3.21 meq/L per day = .64 meq/L per day
If you did daily single batch fast drip, your alk would swing from around 3.21-3.85 meq/L.
If you dose your alk 2x per week at a fast drip(say over half a day period), you would have 3 days of alk consumption before you dose again.
Very roughly speaking, you would have an alk swing on the order of 3 x .64 meq/L = 1.92 meq/L
So if your alk at the top end was 3.85 meq/L, your low would be towards 1.93 meq/L.
Then you do your next fast drip and your alk would shoot from below 2, all the way back up to ~3.85 meq/L.
If anything like that is happening, I'd expect problems with clams, montis, and acros.
Ok, for the sake of demonstration, I went ahead and simulated a couple of fast kalk additions and measured alk to get some sample readings.
The premise is that someone quickly doses ~4 liters of saturated kalk water to a tank with 75 gallons total system volume.
(4 liters X 1000ml/liter)/(75 gallons)/(16 cups/gallon)=3.3 ml/cup
So to make things easy, I figured 4ml of kalk water to 1 cup of tank water would be a reasonable approximation.
I took an 8oz sample of tank water and tested the starting alk using the API reagent with my high precision syringe method.
Next I dosed 1ml of saturated kalk water to the 8oz sample to simulate adding 1/4 of a days worth of top off very quickly. I stirred the sample then measured again using the modified API method.
After that, I added 3ml of saturated kalk to the sample, mixed well, and did a third alk test.
Results as follows:
tank water + 0 ml total kalk addition : 3.21 meq/L
tank water + 1 ml total kalk addition : 3.39 meq/L
tank water + 4 ml total kalk addition : 3.85 meq/L
So that pretty much shows that fast kalk additions cause jumps in alk levels.
What can make things worse is if you "dose lime water twice a week ( 5 gallons drip in)", and you don't dose slowly and continuously over the week to match alk consumption and keep your alk stable...
i.e. you dose quickly so that there are some days during the week where you don't drip kalk...
Your clams and corals will suck your alk down low on the non drip days. Then you bump it back up with the next batch that you drip. And that's on top of the pH swings from the nondosing/fastdosing procedure.
Using the above numbers as an example....
Let's say that your system uses 3.85-3.21 meq/L per day = .64 meq/L per day
If you did daily single batch fast drip, your alk would swing from around 3.21-3.85 meq/L.
If you dose your alk 2x per week at a fast drip(say over half a day period), you would have 3 days of alk consumption before you dose again.
Very roughly speaking, you would have an alk swing on the order of 3 x .64 meq/L = 1.92 meq/L
So if your alk at the top end was 3.85 meq/L, your low would be towards 1.93 meq/L.
Then you do your next fast drip and your alk would shoot from below 2, all the way back up to ~3.85 meq/L.
If anything like that is happening, I'd expect problems with clams, montis, and acros.