kh is constantly dropping....getting frustrated

So I need some advice.  My KH is constantly dropping, but other params seem fine.  I bought a big ol bottle of KH buffer and adding the max recommended dosage daily, as not to raise it too fast.  The best that will do is keep it where its at or just slightly raise it temporarily.  When I don't dose everyday, my levels drop.  Every time i test, they are lower.  Right now it is at 6 which I know is definitely not good, and I can't seem to get it above 7.  Yes, water changes will increase it, but only for a few days.  Using RO/DI water which tests at 0 kh, but at 12 after adding reef crystals.  I was even doing them weekly for a while to try and raise it.  It helped, but that is waaay too much work and too expensive.  I am really started to get frustrated because all the related levels seem fine (mg, ca, ph).  Anybody experienced this and/or know how to fix it?
I would really appreciate any advice as my corals have stopped growing and coralline is fading away and I don't know if it related but have been battling a cloudy film on glass that films over daily after cleaning.
Specs/Params
Calcium - 440
Magnesium - 1,350
pH - 8.0
Nitrate - 0
Phospate -.01
Temp - 78
Salinity -1.025
72 gal w/ 30 gal sump w/cheato & miracle mud, 2 carbon filters, and phospate media
100 lbs live rock
2-3" sand bed
average fish stock
numerous softies of all kinds
Thanks!!!

 

Yeah I thought the same thing so I have tested with multiple different test kits for each and seem to get similiar results.  You are right though, I should probably do that anyways.  Thanks!

 

Yes, numerous LPS', only a couple SPS.
LPS - multilple Duncans, acans, hammers, frogspawns, huge gonicopia, one small brain coral/favia?, alveopora, candy canes, torch


SPS - only a coupl frags - Green digi, whats left of a birds nest, and what kinda looks like a fuzzy horn?
also TONS of mushrooms, rics, and a giant forest of pulsing zenia, and anthelia

 

Sounds great, I dont have any dosing pumps/controllers though....I should probably get something.  I dose kalk manually, but thats a joke trying to keep up with it....also seems to raise only ca, not much for alk and my ca is already pretty steadily high from 440-460 usually, since I dont have much SPS I assume.  Seems like when I do dose, my corals get pissed at me.
Any suggestions for cheaper auto dosing pumps/methods?  I dont have ATO either. 


Thanks for all the good replies guys!  This is my first "help" post.

 

glaspie69....yes kind of.  The green digi has gotten lighter, but I have only had it about a month and never had much success with SPS' so it didn't seem odd to me...plus my formely great tenant flame angel has become not so great as he likes to nip at it...nothing else, just it.  The fuzzy horn looking thing (haha I obviously dont know my sps well) has been consumed by the massive zenia forest, I need to dig it out to get a good look at it.
Are you on to something?

 

glaspie, missed your second post.  The ca does not dissapate, that is why I dont like dosing anything with ca.  It stays high naturally, just the kH is dropping.

 

Yeah, thats what I thought, that if one is consumed, the other should too. Seems the general consensus is that I need to get water tested by a third party. I will try that. Should I just take some to the LFS? I have always tested myself. Also, wont the ph be off from water in a closed container until I get to the LFS? Or should I not worry about ph and just see what they get for kh and ca? Out of all my testkits pH seems to be the only one that seems possibly inaccurate so I am curious about that one.
Thanks again for your help, I need to quit trying to figure everything out on my own! /DesktopModules/ActiveForums/themes/_default//emoticons/smile.gif ...its stressful and expensive

 

Im in Des Moines so I would probably just head up to Adams or IPF. I'll try one of them and let you know what I find out

 

Yeah Im going to try that and see what they come up with.  I dont really like dosing at all besides a little purple up every other day, which Ive cut back on while trying "kent pro buffer dKH" to raise the kh.  I try to keep everything as natural as possible and do water changes as much as possible (which is why prob why ive never had great sucess with sps, but I mainly have LPS anyways).  I would probably appreciate dosing better if I do set it up on a slow steady dose, been meaning to get into the whole autodose thing anyways.  sounds like you started in a similiar situation.  Thanks

 

They are saltwater.  I test with Salifert, but bought new API to test with as well to verify any questionable tests, especially the kH.  But both seem to be pretty close in everyting but ph, I swear it is different everytime I test, but I dont do a good job of testing it at the same time of day, which Ive heard you should.
I do not run pellets (was actually getting ready to until this whole low kh issue), no vodka or vinegar.  does phosban in a filter sock in the sump affect it maybe? only carbon source is from 2 emporer bio-wheel filters in the sump with carbon filters (bio-wheels removed of course).
btw...I added FIJI mud to the sump about 3 mos ago, been battling low kH for about a month now...could this be related? if anything, that should increase it right?  cant think of any other recent changes really