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sandrsReef · 06/30/2010, 11:58 AM

hi randy,

first i want to say that your articles have been very informative and i appreciate the scientific approach to explanation versus speculation and advertising.

i have a question about calcium, alk, and magnesium. we've got a 3 month old (in our care) reef tank that we purchased as an established, yet neglected, fish only tank (the owner had around 1 year i believe). the nitrates were off the charts, and we had no clue about alkalinity or magnesium testing for the first month or two.

i've been doing a lot of reading and research in the last few months (i built my own overflow and sump for a 75g display tank with 55g sump), and recently it's come to my attention via a LFS in the area that our Mg levels are low (about 750ppm), however our Ca2+ levels are around 440ppm and our KH as tested by our API test kit is coming out consistently between 17 and 20.

we recently started dosing limewater within the last 3 weeks after reading an article of yours on limewater and verifing that information across multiple sources.

we're now concerned about our KH values (however they seem balanced per your chart in http://www.reefkeeping.com/issues/20...ture/index.php .... hence my confusion

the API test kit, and the LFS suggest that our KH value is too high and is probably related to low Mg levels. my girlfriend suspects that the limewater may be precipating the Ca2+ out of our water column, however i've not seen any "snowing", and i suspect that things are ok with the drip procedure i've been using for the limewater dosing overnight. i understand low Mg levels, but how can KH be too high??

since starting the dosing with the limewater for makeup water, we've noticed an increase in coralline algae, and it would appear that our frogspawn and blue ridge coral are doing better now... however, with our lack of experience i understand that it could also be coincidental.

our most recent water parameters:

pH ... 8.3
SG ... 1.026
Ca2+ ... 460
Mg ... 750
dKH ... 18
PO4 ... 0.5
NO3 ... 20 (elevated due to recently purchased valencienna goby stirring up the sand bed? normally around 8 or so)
NH3+NH4 ... 0

can you please clear my confusion on our KH values? ...our low Mg levels? ...and possibly clear up some of the concerns with dosing limewater (will it precipitate Mg and Ca2+ if it's "dripped too fast")? ... could the limewater be binding the Mg ions and lowering their availability to the system, and if so is that a problem?

the LFS in our area also recently advised dosing with PurpleUp. what are your thoughts on this product?

lastly, we have been a little neglect in our water change routine... we only had one or two KH tests since before our last water change about 3 or 4 weeks ago, and it was reading about 14 dKH...

i just came across this article ( http://www.advancedaquarist.com/issues/nov2002/chem.htm )of yours after more research before finalizing my thoughts/questions, and it appears we're in zone 1. does this make sense? and so we'd just stop what we're adding and leave it alone? except maybe some Mg??

06/30/2010, 11:58 AM	#17
sandrsReef Registered Member Join Date: Jun 2010 Location: M'boro, TN Posts: 6	hi randy, first i want to say that your articles have been very informative and i appreciate the scientific approach to explanation versus speculation and advertising. i have a question about calcium, alk, and magnesium. we've got a 3 month old (in our care) reef tank that we purchased as an established, yet neglected, fish only tank (the owner had around 1 year i believe). the nitrates were off the charts, and we had no clue about alkalinity or magnesium testing for the first month or two. i've been doing a lot of reading and research in the last few months (i built my own overflow and sump for a 75g display tank with 55g sump), and recently it's come to my attention via a LFS in the area that our Mg levels are low (about 750ppm), however our Ca2+ levels are around 440ppm and our KH as tested by our API test kit is coming out consistently between 17 and 20. we recently started dosing limewater within the last 3 weeks after reading an article of yours on limewater and verifing that information across multiple sources. we're now concerned about our KH values (however they seem balanced per your chart in http://www.reefkeeping.com/issues/20...ture/index.php .... hence my confusion the API test kit, and the LFS suggest that our KH value is too high and is probably related to low Mg levels. my girlfriend suspects that the limewater may be precipating the Ca2+ out of our water column, however i've not seen any "snowing", and i suspect that things are ok with the drip procedure i've been using for the limewater dosing overnight. i understand low Mg levels, but how can KH be too high?? since starting the dosing with the limewater for makeup water, we've noticed an increase in coralline algae, and it would appear that our frogspawn and blue ridge coral are doing better now... however, with our lack of experience i understand that it could also be coincidental. our most recent water parameters: pH ... 8.3 SG ... 1.026 Ca2+ ... 460 Mg ... 750 dKH ... 18 PO4 ... 0.5 NO3 ... 20 (elevated due to recently purchased valencienna goby stirring up the sand bed? normally around 8 or so) NH3+NH4 ... 0 can you please clear my confusion on our KH values? ...our low Mg levels? ...and possibly clear up some of the concerns with dosing limewater (will it precipitate Mg and Ca2+ if it's "dripped too fast")? ... could the limewater be binding the Mg ions and lowering their availability to the system, and if so is that a problem? the LFS in our area also recently advised dosing with PurpleUp. what are your thoughts on this product? lastly, we have been a little neglect in our water change routine... we only had one or two KH tests since before our last water change about 3 or 4 weeks ago, and it was reading about 14 dKH... i just came across this article ( http://www.advancedaquarist.com/issues/nov2002/chem.htm )of yours after more research before finalizing my thoughts/questions, and it appears we're in zone 1. does this make sense? and so we'd just stop what we're adding and leave it alone? except maybe some Mg??