Diatoms, Dinos, or Cyano?

[DonF]

We are still newbies. Tank has been up for a year. We have been battling this for months.

A month ago we turned off lights for 4 days and it all cleared up. Since turning them back on, we are running a new lighting program that is much more blue. We also invested in an RODI and started making our own 0 TDS water (previously we were buying it at the LFS, and I assume it was also 0 TDS). We’re doing weekly 5 gallon changes. Total system (display + sump) is 43 gallons, but I’ve no idea how many gallons are displaced by sand, rock, skimmer, etc.

Anyway, it’s back. We vacuumed the sand three days ago, so the picture shows growth since then. In addition to what’s visible on top of the sand, the rock is getting covered, though I’m not sure if it’s the same thing that’s covering the rock? Perhaps not, because at night the sand looks clearer, but the rock looks the same.

Maybe 4 months ago we added “coralline in a bottle,” and a couple of snails and a hermit now have what look like coralline spots on their shells. I mention this only because adding that seemed to have kicked off a mini cycle (bottle says it has “nitrifying bacteria”), and this diatom bloom (if indeed these are diatoms) started not long after.

Snails, crabs, peppermint shrimp, nor lawnmower blenny are interested in what’s on the rock.

NH3/NH4 - 0.2
Phosphate - 0.25
Nitrate - 0.0
Ammonia - 0.0
pH - 8.0

We are installing an Aquafuge 2 small (2.5 gallon) HOB refugium with LEDs in the sump, today. Chaeto and Pods are in the mail.

Finally, we don’t know how to gauge flow, but I’ve read that high flow might help solve this issue. The return pump can do 1,100gph, but we have it set to about 60% power. Do we turn it up? (Probably will need to add more water to the system if we do that.)

The power head can be seen to the left of the clown fish. We have it set to pulse on and off 24x7. Should it be set lower in the tank (seems to blow shrimp too hard, and maybe also the frog spawn when we move it lower)?



Sorry for the long post, and thanks to anyone who read the whole thing!

 

[andrewey]

Can you get a picture closer to the sand bed or rock? Notice any bubbles with the brown stuff? Notice any strings? At first blush, it looks like diatoms, but a closer picture might help.

As far as flow, I wouldn't play too much with it yet until you get an ID.

Any reason your nitrate is 0?

 

[DonF]

Can you get a picture closer to the sand bed or rock? Notice any bubbles with the brown stuff? Notice any strings? At first blush, it looks like diatoms, but a closer picture might help.

As far as flow, I wouldn't play too much with it yet until you get an ID.

Any reason your nitrate is 0?

Thanks for the quick reply! New pictures with only white light.

Test was done a few hours after a water change, which may be why nitrate was 0. I will retest, now. Also, all we have is an API test kit, which I’ve read isn’t terribly accurate.

No bubbles or strings. It’s kind of “dusty” and vacuums up easily.

 

[andrewey]

It looks a lot like diatoms to me.

To make sure, if you use a turkey baster or blow the rock, do pieces/chunks come floating off the rock?

If it's diatoms, that would fit the current picture- a lot of those coraline in a bottle products have higher levels of silicates which could fuel your diatom bloom. In addition, if your nitrate is near 0, that could also lead to this issue.

The good news is the diatoms issue can be rectified with good housekeeping and likely with you getting your aquafuge installed and dropping the phosphate a tad, you might be able to tackle this slowly without doing a whole lot. If that doesn't work, you can try feeding a bit more to get that nitrate a bit higher. Then again, if this problem took months to develop, I wouldn't try and correct it too quickly. Pretty easy to overshoot the issue and make a way worse issue

 

[DonF]

It looks a lot like diatoms to me.

To make sure, if you use a turkey baster or blow the rock, do pieces/chunks come floating off the rock?

If it's diatoms, that would fit the current picture- a lot of those coraline in a bottle products have higher levels of silicates which could fuel your diatom bloom. In addition, if your nitrate is near 0, that could also lead to this issue.

The good news is the diatoms issue can be rectified with good housekeeping and likely with you getting your aquafuge installed and dropping the phosphate a tad, you might be able to tackle this slowly without doing a whole lot. If that doesn't work, you can try feeding a bit more to get that nitrate a bit higher. Then again, if this problem took months to develop, I wouldn't try and correct it too quickly. Pretty easy to overshoot the issue and make a way worse issue

Awesome, this is good news.

So, I believe I transposed nitrate and nitrite results when I recorded them last week. I just retested (I’m 3 days out from last water change), as new numbers are:

Nitrate - 10ppm
Nitrite - 0
Phosphate - 0.25ppm

I just blasted the rock with a baster and it came off as a mix of dust and flakes. The flakes looked white under the blue lights, though. Not sure they weren’t bits of food that settled in the crevices.

Slow and steady she goes, then. I appreciate your help!

 

[andrewey]

Yeah, that sounds like detritus or just fish food/poop. Your numbers seem good, so I'd stay the course and install your aquafuge and see if the diatoms don't burn themselves out. If they don't, then you were right on the money in terms of playing with your flow again (at least for the diatoms on the sand).

 

[DonF]

Yeah, that sounds like detritus or just fish food/poop. Your numbers seem good, so I'd stay the course and install your aquafuge and see if the diatoms don't burn themselves out. If they don't, then you were right on the money in terms of playing with your flow again (at least for the diatoms on the sand).

Last question - when you guys talk about flow, are you talking about flow from sump to display tank via return pump, or power head(s)? Or both?

When I crank the return pump higher it will quickly deplete the sump chamber it’s in and start sucking air. I might be able to bump it a bit higher if I add some more water to the system, but I have to be careful that it’s not so much that the sump would flood in the event of a pump failure.

For the power head we just put it in a spot where our frogspawn seems to get moved about a little with each pulse. Even when it’s off I can see there is still a decent current created just from the return pump by watching the shrimp.

I guess I’m asking if the next step would be moving the power head lower so it stirs up the sand or cranking the return up higher? I should have mentioned that we have a sand sifting gobi that moves sand all over the place. He isn’t bothered by diatoms and slurps them right up.

I can start a new thread with a video if we go down the flow road, I guess.

 

[Jason mack]

Awesome, this is good news.

So, I believe I transposed nitrate and nitrite results when I recorded them last week. I just retested (I’m 3 days out from last water change), as new numbers are:

Nitrate - 10ppm
Nitrite - 0
Phosphate - 0.25ppm

I just blasted the rock with a baster and it came off as a mix of dust and flakes. The flakes looked white under the blue lights, though. Not sure they weren’t bits of food that settled in the crevices.

Slow and steady she goes, then. I appreciate your help!

If your phos is 0.25 ..its way too high and probably the reason ..po4 should be 0.05 -0.1

 

[andrewey]

With flow, it's a combination of everything (return plus powerhead). THat being said, flow's a bit tricky to nail because you could have plenty of water movement (gph) through your powerhead or return, however based on the geometry of your tank, rockwork, and coral placement, the flow could be lacking. Sometimes this means adding another powerhead to take care of dead spots, sometimes this means moving your current pumps around, and other times it means moving your rocks or coral.

Before you go that far, I would focus on getting the refugium in line. That should drop your phosphate a bit and you should start to see the diatoms going down.

 

[Jason mack]

Last question - when you guys talk about flow, are you talking about flow from sump to display tank via return pump, or power head(s)? Or both?

When I crank the return pump higher it will quickly deplete the sump chamber it’s in and start sucking air. I might be able to bump it a bit higher if I add some more water to the system, but I have to be careful that it’s not so much that the sump would flood in the event of a pump failure.

For the power head we just put it in a spot where our frogspawn seems to get moved about a little with each pulse. Even when it’s off I can see there is still a decent current created just from the return pump by watching the shrimp.

I guess I’m asking if the next step would be moving the power head lower so it stirs up the sand or cranking the return up higher? I should have mentioned that we have a sand sifting gobi that moves sand all over the place. He isn’t bothered by diatoms and slurps them right up.

I can start a new thread with a video if we go down the flow road, I guess.

When talking about flow we mean from wave pumps .. when talking return pump that's your tanks turn over ...so find your level for your tank..qus power of return

 

[dwest]

Last question - when you guys talk about flow, are you talking about flow from sump to display tank via return pump, or power head(s)? Or both?

When I crank the return pump higher it will quickly deplete the sump chamber it’s in and start sucking air. I might be able to bump it a bit higher if I add some more water to the system, but I have to be careful that it’s not so much that the sump would flood in the event of a pump failure.

For the power head we just put it in a spot where our frogspawn seems to get moved about a little with each pulse. Even when it’s off I can see there is still a decent current created just from the return pump by watching the shrimp.

I guess I’m asking if the next step would be moving the power head lower so it stirs up the sand or cranking the return up higher? I should have mentioned that we have a sand sifting gobi that moves sand all over the place. He isn’t bothered by diatoms and slurps them right up.

I can start a new thread with a video if we go down the flow road, I guess.

Usually when we say increase flow, it’s with power heads inside the tank. You can increase the return pump flow, but it sounds like that is probably more trouble than it’s worth. It sounds like the powerhead is in the right place considering your coral, but it might help to move it some. You’ll have to play around with it. I wouldn’t worry about the shrimp.

i agree that the stuff looks like diatoms, but it’s very hard to tell. I bet they will go away with your husbandry. If not, you can get a cheap microscope and know for sure. If it were my tank, I would let it ride for a while first.

 

[DonF]

The refugium is in! If anyone has a Red Reefer 170, the Aquafuge 2 (small) fits in the sump like a puzzle piece. Perfect!

We didn’t buy the bubble trap accessory, and we’re not sure it would even fit with our skimmer. Some filter media and the side of the skimmer made a perfect bush fix to stop the waterfall, however, and it’s dead silent.

Fun project with my son. Now, let’s see if helps with these diatoms (after the chaeto arrives).

 

[DonF]

One more update: We rearranged our skimmer and refugium pump, and made a better solution to quiet the refugium return. While already elbow deep in futzing, we decided to turn up the main tank’s return pump.

In the past maybe we didn’t open the display tank drain valve enough and that’s made the pump deplete it’s sump chamber, but no issues this time. It’s now on max power and we have approximately double the turnover rate. Also moved the wave pump to opposite side of tank since diatoms were only appearing on the side where it was.

Let’s see what happens, now... vacuumed, today, and changed some water. Chaeto is in, too.