gaa!!!!!! This is so frustrating!

My parameters are out of whack and i don't know why. I've got a 75 gal DT with sump and fuge. Total volume of the system is about 105 gal. I had been using well water and IO reef salt for the last year. In January, I got my RO/DI up and running. I also switched to Oceanic salt at the same time. In order to try to "flush" out the old stuff, i've been doing a bunch of water changes - 15 gal at a time, 2-4 on weekends for a few weeks, so a total of about 10 of these now. By serial dilution, that should have brought "contaminants" from the well water down to less than 50% original. This is all in an effort to finally rid my tank of algae (briopsys, mainly).

Just two days ago, i got my bottle of Kent Tech M, so I've done the dose as directed for two days.

I checked my param's today.
spg 1.022 (too low, i think)
pH 8.3 (where its been for a year)
no3 = 0 (stable)
ca > 500 (! its always been around 450)
mg > 1500 (had been around 1375)
dKh = 5

my dKh had been 10-12 for a long time. many months ago it was 8 and i added NaHCO3 for a few days and it settled up at 10-12 and then stayed there with no additions.

my question is - what do i do now? I don't want to make drastic moves and start a crash. Should i sit tight and see what happens? Should I start adding bicarb again? What can i do to stabilize alk long-term. The tank has 120 lbs LR and aragonite bottom layer.

Thanks for advice!

 

Have you tried a different alk test kit? that seems really low if your cal is on.
also do you have corals or just fish?

 

The DKH is low. But other than that you are OK, nothing too get to frustrated or worried over. If you boost the dKH up a little, the CA will probably go down some as well. Add a little salt mix to your top offs to bring the sg up. That may even help balance everything out too.

 

rhorton -
good call. the alk test is API. going to try LFS tomorrow for a different one. Tank has a light coral load and several fish. trying to get a good reef going...

pack - good advice - i was thinking about throwing a little salt in the ato, now will do!

 

Yeah like Packleader said you want to get your sg up esspecially with corals. If it were fish only then 1.022 wouldn't be a problem.

 

Kalk, Ca(OH)2, or baked baking soda is your best bet at long term alkalinity increase. These two also won't negatively affect your pH. My guess is now that you are getting rid of the old well water that undoubtingly has some carbonates to it, the RO water isn't getting "buffered" enough by the Oceanic. Just get back on your bicarbonate regimen and it should be fine.

As far as the bryopsis is concerned, your attempt to raise the Mg can help but I have seen the most success with Mg OVER 1600ppm.
That coupled with stellar water quality.

Good luck!
Happy chemistry!

 

dr f- thanks. i threw in some baking soda last night. now alk is up to 10. i'm going to wait a couple days and re-check everything, with plan to dose baking soda until alk is 12-14. i'm continuing to dose mg, so i can get it up at least to 1600 and see if the "B" starts to die....