Algae bloom AFTER Water changes?

[js_marra]

So hoping for some input, although I know there can be a number of reasons.....

After my past few water changes I have noticed I get a brown diatom bloom on my sand bed almost immediately (within the hour it seems) after my water change. I have a 10g AIO tank and do about 15% water change every week with RO water. I use Tropic Marin pro reef salt.

I thought maybe my RO source water was not as clean as it should be. I buy from a local LFS, a very reputable one. As a theory, I started getting my RO water from another LFS and still getting the diatom bloom. Nitrates and phosphates are both undetectable for the most part. Nitrates sometimes around 0.5ppm. I feed pretty light and only have two clowns and corals as my livestock besides the clean up crew.

Once the diatom bloom comes on, I usually have to turnover the sand for at least 3 days before things settle down. I would think doing another water change would help but that seems to just start the diatoms all over again. It is the strangest thing.

Any thoughts?

 

[Webslinger]

RODI must not be good . What's the TDS

 

[js_marra]

RODI must not be good . What's the TDS

Both LFS stores claim they check daily for 0 TDS. I do not have a meter to double check. I have also used their RO water in the past many times and only until recently I have had this problem.

 

[Webslinger]

get a tester/ get your own rodi unit. Pure water wouldn't cause any bloom.

 

[Bio32]

So hoping for some input, although I know there can be a number of reasons.....

After my past few water changes I have noticed I get a brown diatom bloom on my sand bed almost immediately (within the hour it seems) after my water change. I have a 10g AIO tank and do about 15% water change every week with RO water. I use Tropic Marin pro reef salt.

I thought maybe my RO source water was not as clean as it should be. I buy from a local LFS, a very reputable one. As a theory, I started getting my RO water from another LFS and still getting the diatom bloom. Nitrates and phosphates are both undetectable for the most part. Nitrates sometimes around 0.5ppm. I feed pretty light and only have two clowns and corals as my livestock besides the clean up crew.

Once the diatom bloom comes on, I usually have to turnover the sand for at least 3 days before things settle down. I would think doing another water change would help but that seems to just start the diatoms all over again. It is the strangest thing.

Any thoughts?

are you leaving lights for extended periods?

 

[js_marra]

are you leaving lights for extended periods?

Lights are on their normal schedule. I have actually started doing water changes in the evenings before lights go off to see if lights were causing it and I still wake up to an algae bloom in the morning on the sand bed. So I think that rules out the lights

 

[NS Mike D]

if it's diatoms, then the culprit would be silicates. My understanding is that they can get past the rodi and the TDS meter. (something about them not having enough "charge" to be detected.

There was a thread on this the other day.


first, is it RO water or RODI water? LFS should be selling RODI not RO (unless the RO os for fresh water)

Secondly. get a silicates test kit and see if it's in your R0/RODI water.


In that thread, the OP was going to run his RODI water through a gfo reactor and GFO absorbs silicates and you needed worry about bottoming out PO4 in your water mix (tank water is another story).

 

[NS Mike D]

another thing. if nitrates and phosphates are zero, that can lead to far worse problems. If you are using API test kits for these, it may not be an issue.

If you are using more reliables test kits, you are at risk for cyano and worse, dinos. So nail down those levels ASAP.

 

[js_marra]

another thing. if nitrates and phosphates are zero, that can lead to far worse problems. If you are using API test kits for these, it may not be an issue.

If you are using more reliables test kits, you are at risk for cyano and worse, dinos. So nail down those levels ASAP.

It is RODI. I also think it is likely to be silicates in the water. The tests for nutrients are salifert tests so they are reliable. I have always struggled with this tank to get detectable nitrates, but also fear for the cyano and dino outbreak. It is lighly stocked, no skimmer, but has a lot of bio media. Maybe I should up the feeding