Trying to stop Precipitation on UV glass shield?

[AD87]

Hello, I am trying to either stop or greatly reduce the precipitation on my UV glass shield. It builds up in about 2 or 3 weeks. I am currently using a 2 part dosing system ESV brand. Is there anything I can do to stop it or reduce?

[Allmost]

what are the values for Ca++, KH, and MG ?

try to keep it balanced. keep CA++ at 420 PPM. keep the KH you are at. and figure out the correct MG concentration frm here

http://reef.diesyst.com/flashcalc/flashcalc.html

[AD87]

8dkh
410 cal
1320 mag
50 gal total
Tank has only 2 large anemones and 2 sps frags and 400 zoas so my demand isnt that high

[swcc]

your levels should be good to not have a precipitation problem. How much do you dose and what is your method?

[AD87]

Im dosing manually ESV 2 part i dose about 30ml of both cal and alk. The alk i usually add 15 ml at a time slowly into my powerhead area to insure it's spread.

[tmz]

The heat contributes to it. Moving your dosing point away from the intake to the uv chamber might be help.

[bertoni]

The high pH of the supplement and any higher temperature inside the pump both will encourage precipitation. The UV will add some heat, too. I'd try to dose away from any inlets.

[AD87]

I dose in the main so its get dispersed then would have to travel down my overflow then to my sump through 2 chambers in my 20 gal sump then return pump to the uv then back to my main. My goal is not to have to break down the uv and clean it every week due the the build up making the uv ineffective. Does anyone else have any other suggestions?
Thanks for all the suggestions .

[Bio-nut]

TMZ is correct on the thermal influence. This is seen continiously in evaporative cooling systems. Increased temperature drives the formation of percipitation. No matter where you dose your two part it will still have the same effect. The only thing I can suggest is that you run the return from your chiller through the uv sterilizer to aid in temperature reduction. This will not fix the issue completly but it will lenghten the time period between having to clean the glass tube.

Lastly, if the tube is scratched it provides a surface for crystal formation, this can occur from you trying to clean the tube. Possibly replaceing the glass tube will also help you in this area.

[AD87]

Bio-nut thats a good idea, but i dont use a chiller.

So is everyone telling me that there is nothing i can do?

[bertoni]

What are the alkalinity, calcium, and magnesium levels in the tank? Are you sure this is calcium carbonate buildup?

[AD87]

8 dkh
Cal 420
Mag 1320

Yes it comes off with muriatic acid instantly.

[bertoni]

Those parameters are reasonable. I might let the calcium drop to 370 or so. That might reduce the precipitation, at least a bit. Natural seawater is more like 350 ppm or so. We tend to run a little higher in our tanks because the levels shift over the day, and to encourage a bit more growth. In this case, I'd personally value ease of maintenance over growth.

Increasing the flow through the UV filter might help as well, although it will reduce its kill ratio. The increase flow might keep the temperature a bit lower. I might try measuring the temperature at the output by collection a sample, if that were easy enough.

Increasing the magnesium level a bit might in theory help as well, although I am a bit skeptical.

[tmz]

It's been several years since I've taken my uv sterlilzers off the shelf but I did use them for several years without much precipitation on the quartz tubes. Alk, calcium and mag were higher than yours.
BTW what's the ph ?
aquarium water temp?
Could be dwell time and heat( higher temps reduce CACO3 slolubility) or peaks in alk and/or calcium depending on how evenly you dose them over time .
I agree with Jonathan's suggestions and don't have much else to offer.
Since you are not dosing near inlets localized temporary concentration is not the issue obviously.
I'd:
see if I could get the uv radiation level I wanted for targeted organisms with a little higher flow trough the sterilizer ;
bump the mag by 100ppm;
review the aquarium water temperature with considration toward keeping it a bit cooler;
review my dosing method for alk and calcium to insure against temporary spikes.

[swcc]

one way to rduce this is to possible set up a slow drip for dosing

[AD87]

Temp is 80-82
I havent checked ph in awhile to be honest. I could setup a slow drip but i wanted that as last option. Ill try to bump the mag to see if that helps.

My kill ratio is right where i want it based on my flow so i dont want to invest in a bigger pump.

[tmz]

Ok, good luck . my aquarium temp was lower ,77 to 80 degrees; not sure that was a deal breaker though but it might drop the heat in the uv. Ph 8.1 to 8.3. Slow spread out dosing on alk and calcium .

[AD87]

I am still having this issue...

Does anyone know any tricks besides taking apart the UV every month?

[bertoni]

Higher flow might reduce the amount of heating that occurs, although it'll reduce the kill rate for some organisms. Higher magnesium might help a bit, too. I might try measuring the temperature of the output water. I might just run the UV unit into a cup for a while and take the temperature.

[GimpyFin]

^^This^^ Flow and heat are the biggest contributors, IME/IMO. I have an aqua uv that i use on occassion. At one point I had the flow setting fairly low and I had precipitation build on the quartz sleeve. After increasing the flow through the uv, I didn't really have an issue.

[tmz]

I don't have anything else beyond my posts from 4 years ago, i.e.: post #6 and #14.

[Apotack]

You could stop using the uv, probably not needed.

[AD87]

Thanks for the tips everyone. I will update the thread if anything suggested works.