Can Kh go from 20 to 2 in 5 days?
 

First off I admit I'm a careless doser and tester. PurpleMonkey will attest that my tank seems to be a freak and get away with things most other tanks don't.
Most consistant I dose Brightwells 2 part.

I randomly tested one day and found my Kh to be 20. So I stopped all dosing (Except Kents Mg... trying the nuke the algae theory)
4-5 days later I test again and my Kh is supposedly at 2. I tested 3 times with a Seachem kit.

there are NO noticeable differences to the tank inhabitants. I've noticed no unusual precip of powder...
can I really use up that much alk in 5 days?

40 gallon breeder w/sump - approx 60 gallons water.
heavy on the SPS, LPS and 2 clams.

All other parameters normal.
Ph 8.3
Nitrate, ammonia, nitrite = 0
Phos - 0.05
Mg 1900
ca 500 (also dropped from 700 5 days ago)

There's something wrong with the test kit, my kh is at 10 with salifert, if you want you can test against my water to see where the test kit stands??

It'd better not be the test kit... ok well yeah better that it;s the kit and nothings wrong, but I just got it from JL's 3 weeks ago. I'm gonna be choked if it's already gone bad somehow.

The saliferts were on sale at OA got my alk for $13

I hardly test but since it was so cheap, why not.....

As I said your welcome to stop by and test if you're curious or alternatively test harp's tank since he's closer.....

The Kit seems to be in good condition...
I forgot SeaChem kits come with a reference solution if in doubt. tested it with reference and it was spot on.
So.... guess I gotta start dosing again....

Take some water into JL or OA and get the boys to test it for you, compare it to your results and go from there.

look at your Ca and look at your Alk. you had a percipitation event if thoes numbers are corect. 700 Ca is way way to high and will percipatate out your alk. and it can work the other way also.

you Mg is out to lunch as well it should be about 1350.

Being a carless doser is the bigest problem here. you need to learn to test and dose on a regular basis and not dose if it is not needed.

I would recomend testing befor you dose to determin how much you need to dose. keep a log and record this and eventualy you will be able to do daily dosing and only test once a week to make adjustments to your amounts. just adding stuff for the sake of adding can cause big problems and affect the stability of your tank, and most of all cost you a lot of extra money.

Steve

the mag is intentionally high right now cause I read that thread somewhere that dosing above 1600 with kent magnesium may knock down some algae growth.
While I don`t have a huge problem of it there are some patches I can`t get rid of.