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Cloudy Water After Water Changes (1 Viewer)

justin81

justin81

Senior Member
Joined
Apr 30, 2018
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176
Location
Lonsdale
The past 3 water changes I have done have caused very cloudy water the next day. The water is white and cloudy and lasts for about 48hrs. All my LPS close up but my SPS and fish do not seem to react to it. I'm trying to find the root cause of this issue. I have read it could be a bacterial bloom, but I have a 15 watt UV sterilizer running 24/7. I thought it could be alk precipitation, but it doesn't happen until the following day.

Hoping someone has a opinion on what it could be.

I do a weekly 5 gallon water change every Sunday using Reef Crystals. I mix for about 24hrs prior to use and bring the water to 80 degrees before doing the change.
The only changes from the previous water changes is I am on my last bag of salt in the box.

Current Parameters
Salinity - 35ppt
Temp - 80 degrees
Cal - 480
Kalk - 9.0 dkh
Mag - 1400
NO3 - 5.0
Phos - 0.03
 
Have you tested the parameters of the freshly made salt water? Tested your tank before the water change and during the cloudy period?
 
I've tested the tank before and after the water change and parameters are the same. I will test some fresh mixed saltwater tomorrow. That is a good idea. Thanks!
 
How big is your tank? If you are doing 5 gallons a week I am guessing it being about 30-50 gallons. How long has the UV been on the system? Does 100% of the water go through the UV?

A 15 watt is supposed to be good for up to 75 gallon tanks (debatable range). Could have possible killed off the beneficial bacteria causing the tank to cycle. Depends on flow if this is even possible.

Are you mixing your own saltwater? Using RO or tap water or well water? When was the last time filters or Resin was replaced in RO unit?

If there is a chance there is bacteria being added introduced with the new salt water, your UV could be resolving it in a matter of days verses a week or two without the UV.

Could always try and turn off the UV.
Could try adding some beneficial bacteria or stability to the new saltwater.

Just spit balling some ideas.
 
I've seen this question on this forum before in the past. I've also experienced this myself when my tank was kind of new. The tank was done with the cycle and everything was clear for maybe a year or over a year, but I did a 'water change' and the whole thing turned cloudy white. It went through a mini cycle for a week or 2 before it got back to normal again. I agree with the point that @MistakesWereMade above. That's a bit more technical than what I would usually think. But basically, my opinion is that my tank had enough good 'stuff' to stay in balance before the water change, but I over did it with the water change. I replaced too much old water. I cleaned out the sump. I replaced the filter floss. I replaced the activated carbon, etc, etc. Basically, I did everything all at once, got rid of too much good 'stuff' with the new 'stuff', and threw my tank out of balance so it went through a cycle again. This would likely happen in my case because I usually rely on the 'live' stuff to keep my tank in balance (live rock, live sand, etc). But if my tank water volume is much more than what my 'live stuff' can handle (or can barely handle) to keep it in balance and I replace a large quantity of something, it would immediately throw my tank out of balance right away. So, in this case, if it were me, I would try not to over do it until I know my tank is ready for it. I might consider doing a smaller water change. Or I might change out the filter floss on the day(s) before, and change out the water the next day(s) instead, instead of doing everything at the same time. It's just my 2 cents here :).
 
Thanks everyone for your replies! I'll try and go in order

I tested a small 1 gallon batch of Reef Crystals today and results were 480 Calc, 12dkh, and 1400. I don't think adding 5 gallons of 12dkh water to the tank at 9dkh would cause precipitation, so I'm kind of crossing that off the list.

The tank is 75 gallons. The UV was in stalled in June, so only 7 months old. I was planning on changing it at 12 months, but I do clean the sleeve once a month due to the kalk reactor.

I use a BRS 4 stage 75gpd RODI system and do a ICP test every 3 months, but the ICP would not show bacteria in the RODI water test. I am due for a full filter and membrane change out though. I replace them every Super Bowl as a reminder. I'm wondering if bacteria is in the filters themselves maybe causing a bloom???

I think I will make one change at a time and start with changing the filters and membrane in my RODI unit and do a 2 gallon water change and see how that goes. I'll swap out my filter socks the day before as well instead of the day of the water change.

I'll update Sunday! Thanks again for the advice!
 
Quick update, I did a small 2gal water change but forgot to change out the filter socks. There was no bloom this time.

This got me thinking maybe it's something with my filter socks. I wash them in non-scented bleach in the washing machine and then do a water only rinse afterwards. My wife said she bought a different brand of bleach about 5 weeks ago, so now I'm thinking it may have something to do with that.

I'm going to change one filter sock today and see what happens.
 
When I used filter socks, I would do one cycle with bleach with an extra rince cycle. Then I would do another quick wash cycle with no bleach, with an extra rince cycle.

I had almost 20 socks so they would completely dry out between uses.
 
Good point, maybe they aren't being rinsed enough. I will start doing what you are doing with a 2nd wash without bleach and another rinse as well.
 
No bloom or cloudiness after the sock filter change. I guess I'll do another 5gal water change this weekend and see what happens.
 
Last update....... I have no idea what the issue was. I double checked the filter socks, double checked my salt mix, tested the water daily for any changes, and in the end I did a 5gal water change yesterday and no issues. I decided not to change my DI filters yet to see if I could recreate the issue with all the same parameters. Who knows.

I did have some bleaching on my monti caps, but that was the only "damage" from the whole situation, but they are bouncing back.
 
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