Help I keep getting precipitation on glass

[200mfromocean]

PH 8.1
Calcium 400
Ntitrate 0
Mg 1250


There is a fine collecting all over the glass. I just scraped the damn thing last night.

[HighlandReefer]

What is your alkalinity?

What does the stuff look like on your glass (color, texture, etc)?



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[200mfromocean]

White thin film. It has kind of a rough texture. I cannot rub it off in some places. I will have to get the craper to remove it. Also noticed a big drop in calium from 450 to 400 last night. I have just a few frags and 4 " clam. Also ran powerheads in viniger yesterday. I have 40 people coming over tomorrow and want the tank to look nice.

Also did a small upgraded skimmer to icone 200 as of Thursday.

Should I just do a 30-40% water change?

Thanks. Sorry have a hard time putting up pics.

[HighlandReefer]

Sounds to me like this stuff on your glass is calcium carbonate from running too high an alkalinity. I get this at the bottom of my aquarium when I run my alk over, say 12 dKH. It looks kind of like cloudy glass and is very hard to get off, even with a razor blade.

I would let your alk. drop down below 11 dKH by natural consumption rather than water changes. This is guessing that your alk. is high. I have not seen what your's is yet. ;)

[200mfromocean]

The kh was running 15 or 16 per API. Did some scraping last night. Guesse it dissolves and percipitated back most on the display. Light cloudy film and yes it takes elbow grease to get off.

[HighlandReefer]

If you let your alk. drop naturally by stopping all alk. supplementing, kalk dosing and reactors this precipitation will stop once your alk. drops below the 11 dKH mark. It may take a little while for the alk. to drop. Many alk. supplements include many of the products you buy from the vendors for calcium supplementing, FWIW. It's nice to know exactly what is in your supplements you choose to use. ;)

[redfishsc]

kalk is, from what I've experienced, the culprit most of the time.

A razor blade (but not if your tank is acrylic) will work.


If you dose too much, too quick of the kalk--- or even dose alk along with kalk (ie, at the same time) you can get this.

[bertoni]

I agree that calcium carbonate precipitation likely is the issue. You could try dumping some of the film into a bit of vinegar. Calcium carbonate will fizz.

If the calcium is at only 400 ppm now, I would expect the precipitation should stop if the alkalinity when the alkalinity is back down to 11 dKH. If the tank is being dosed with pH buffers, that would explain the high alkalinity and the precipitation.

[200mfromocean]

The dkh fell off pretty quick now 11 with a 20% water change and 10 or 12 hrs of time.

[bertoni]

Okay, the tank should be fine as long as the alkalinity doesn't move up beyond 11 dKH. I'd readjust the dosing schedule as needed.

[66imper]

I just set up a small 20 gallon tank that has the same residue on the glass inside the tank. Using a razor is the only way for me to remove it. I only had 10 gallons of RO water and used tap for the remaining 10 gallons.

I do not have a test kit. I assume a KH/Carbonate Hardness test kit is what's needed to check the levels? You know where assuming can get you.

Will high levels of calcuim carbonate harm or even kill fish?

Thanks for the help.

[redfishsc]

The carbonate you are testing isn't specifically calcium carbonate. Generally calcium carbonate is what forms when calcium and carbonate ions bind together and precipitate out of solution.


It's the free carbonate ions that you are testing for, and that can be not-so-good in higher levels.

I doubt it will harm the fish, I've heard of people putting their reef at nearly 20 dKH (during studies to see how the coral respond). Don't try that at home!!
Short periods of time at high kH values aren't necessarily bad.



For a good cheap and easy-to-use kH kit, get the API kH kit.

[200mfromocean]

Thanks guys. I did not see any ill effect from the big runnup in dkh to 16+ to fish and corals. The calcium tanked along with dkh. Now 350. Perhaps I just got to live with lph levels around 7.9.

[ChrisKirkland]

You might want to test the dissolved O2 in your tank... If you have low O2 in your tank then that would explain the low PH

[bertoni]

Actually, the oxygen level doesn't affect the pH at all. It's possible (and common) for tanks to have both low pH and be at full oxygen saturation. My tanks ran that way in the winter.