A Good ATS That Won't Grow Algae Anymore

[herring_fish]

One month ago, I build version 3 of a light fixture for my very reliable 15 year old Algal Turf Scrubber (ATS) but this time, it has not begun to grow any filamentous algae at all. I did get a little green slim but I didn't even get much of that either. It use to grow lots of algae, no matter how long I went past when I should have replace the lamps.

I am looking at a few reasons why I am not getting any growth. I hope to narrow them down with your help. I guess that I will back up a little.

Background:
I have a 130 gallon display tank and a 55 gallon refugium tank in the garage. It has a deep sand bed of about 8 inches and the rest of it is full of very porous coral rubble, no lights. I only pump 2 gallons of water through that tank and back to the display tank per day. The only life that is in the refugium is bacteria but there must be a lot of it.

Nutrients:
While the dump bucket style ATS aerates the water quite well, it has not grown algae in it for about 3 years so the refugium is the only form of filtration that the system has, no skimmer or anything else. The scrubber stopped growing algae right after I hooked it the refugium. I think that the bacteria out competed for nutrients and starved out the scrubber.

Daily, I feed the display tank about two cubes of Cyclopes, about 3ml of phyto, a couple of pinches of powdered food and a pinch of flake food.
Lighting:

I have a 48 by 6 inch, single sided screen above the display tank. Perhaps there is too much light on the screen. The new fixture has 12 by 20 watt CFL bulbs for a total of 240 watts of CFL light which is roughly the same as 900 watts of regular lighting or about 14,400 lumens. The reflector is not shown above. I have been lighting the scrubber for 12 hours on per day. Version 1 of the fixture had 4 VHOs at 1,000 lumens each for a total of 4,000 and I got great growth. It very well might be that I have way too much light for version 3 but I don't get the regulate symptoms.

I thought that version 2 of the light fixture had good lighting but since the ATS wasn't growing anything, I thought that I would get rid of it go with a lot more light.

I built the newest fixture so that I can cut off 3, 6 or 9 of the lights and still get fairly even light coverage on the screen. My plan, if I decide to tackle the lighting first, is to cut the lighting back, a little at a time, until I get growth.

Minerals:
I was dosing iron and iodine before I recently did a very big water change. I haven't grown any algae since then to deplete what was there so I don't think that is it.

I know that the problem is not water flow turbulence. This is my custom designed and built dump bucket style ATS that is based on the patented true Algal Turf Scrubber ®. While it takes up more space than other styles of ATS's because it is only lit on one side, it is one of the most efficient designs per square inch of lighted screen around because of the turbulence that is generated as the tray dumps and rights itself.

Phosphate:
Another one of the potential problems is nitrate limitation (or too much phosphate). It has been suggested that algae takes up nitrate and phosphate in a particular ratio and if it gets too far out of whack, algal growth is depressed. I disconnected the refugium so the ATS is not competing with it.

_________________Day 1___________________ ___________After 23 Days__________________

Here are the tests to help assess problem one:

I don't what it is that has stopped my scrubber so completely but I need to get it running. If anyone has a fifth or sixth possibility, please let me know.

 

[srusso]

Hard to see, what are your tests reading?

 

[herring_fish]

I am not color blind but I find the tests hard to read. All I can say is that it looks like I have low or very low nitrates and very high phosphates.

 

[srusso]

I am not color blind but I find the tests hard to read. All I can say is that it looks like I have low or very low nitrates and very high phosphates.

What is the actual number the API test reads? Or the highest value, if you think its beyond that...

Start running GFO, you need to correct the balance. Once the API test can no longer read phosphates, get your self a Hanna checker.

This tank is a reef, right?

However,the scrubber should be growing something... even if the tank is nitrate limited. Can you post a picture of the current growth?

 

[herring_fish]

There isn't much to see. The brown is not filamentous algae. It is probably a diatom based coating.

 

[srusso]

From reading the algae it would seem that your not getting enough light onto the screen...
However, there are cases with the waterfall design cleaning very well every 3 days can clear out darker growth like that and get green growing faster. What is the distance of the lights to the water and depth of the water just before it dumps.

Seeing as the scrubber is only a month old it maybe too early to tell for sure...

My vote is to have you clean every 3 to 4 days for a few weeks.... and see if the condition improves...

 

[herring_fish]

The lighting output is extremely high. The lights are two or three inches from the top of the water. The tray is 3 inches deep at the lowest point. Of course it tapers down to zero at the other end.

I will try cleaning it more often as you said.

Thanks

 

[srusso]

The lighting output is extremely high. The lights are two or three inches from the top of the water. The tray is 3 inches deep at the lowest point. Of course it tapers down to zero at the other end.

I will try cleaning it more often as you said.

Thanks

Yeah I would say that your growth maybe normal given the age. Not sure how long it takes a dump bucket to mature but I would imagine its a bit longer then a waterfall.

 

[herring_fish]

Actually, this particular unit has started much faster in the past. The dump bucket concept is optimized for growing filamentous algae. This type of algae grows faster under conditions of intermittent turbulence and changing water flow rates. This design provides higher water flow rates for short periods of time. It basically simulates surface wave action.

It has been suggested that when starting up a display tank you should pre-populate available attachment sights on the glass and rock, with a small diatom bloom by dosing silicates. I did that but my ATS started up just find initially. Perhaps the small attachment sights on the roughed up screen are occupied by things that live under low light or nitrate limited conditions. After all, It wasn't growing any strands for two or three years. The display tank does not have any hair algae anywhere. It does however, grow diatoms on the glass and some rocky surfaces and the surface of the screen is brown, not with brown turf algae but with a diatom coating.

For that reason, I spent extra time scraping the screen down much better than I normally would, after you pointed me toward doing it more often.

 

[herring_fish]

After 5 or 6 weeks of no improvement, I bought a 2 liter container of PhosGuard ($42) and also bought a large professional sock to go with it. I first scraped off the screen that was just growing slime. Then I used the entire contents and placed it directly in the display tank under the dump bucket. In four days, I got the results that are displayed above.

All of a sudden, my glass changed over from brown diatom powder to green. It still came off like powder but there was a definite change in color and it happened very quickly.

I looked at the screen and I think that I saw dark green filamentous algae growing among the slime. I sprayed the screen down to wash away a little of the slime but I didn't scrape it down. I want to see if it is just wishful thinking on the hair algae.

I will keep you posted.

 

[spamreefnew]

what made you choose the dump tray? Is this the only filtration?

 

[herring_fish]

Yes This is the only filtration that I am using now. I started using this scrubber in the early 90's and it worked great for years. I could feed VERY heavily and still keep my nutrients extremely low.

Unfortunately, I tried a to use a sump full of rubble to grow bacteria. This left me with low nitrates but high phosphates. I think that this interfered with my algae growth even after I disconnected the sump. At least that is what I think was the problem.

Now, I am trying a few thing to see what it takes to get it working like it used to.

 

[herring_fish]

Day 41

I got great results and took the bag out after 7 days instead of the 4 that was suggested by directions. Then I waited a week and the phosphates did not go back up. I thought that the rock would release a lot of phosphate. At the same time the nitrates stayed down as well.

Unfortunately, the screen did not go crazy with filamentous algae. It grew a little bit of the filaments but it got covered by green slim algae. I cleaned it and got more of the same.

It seems that exporting slim must be doing something. Export is export, I guess.

Day 55

Now I am trying to rinse of the slim instead of scraping it off so that the hair algae has a chance to get going.

Doesn't anyone have any ideas as to what is going on?

 

[herring_fish]

I just cut the lighting in half, down to six by 20 watt CFL lamps, We will see how that effects things.

 

[JohnnyB in SD]

I've always liked the dump bucket style, wish I had the space to try one.
Having only used a waterfall scrubber, I'll suggest some universal principles for you to consider.

You do have a good reflector behind the CFL bulbs?
What Kelvin temp are they?
What are the dimensions of the effective algae growing area?
How much food are you dumping into the system each day?
Has your feeding regimen changed since the VHO Version 1?

It doesn't sound like you've modified the flow characteristics since the more successful early days?
My first instinct would be to look at the lighting aspects, much like you are doing.
Or perhaps inadequate nutrients, but from that's what I've heard, certainly not my experience.
I would think your nitrates should be much higher if it's a light issue and you're not processing nutrients because of it. With the low nitrates, is it possible that you aren't putting enough nutrients into the system to grow algae, and the excess phosphates are leaching from rock etc?

 

[herring_fish]

Thanks for the thoughts.

The reflector is made from aluminum flashing. When I did some research some years ago, I found that while polished aluminum is best, brushed or even white painted comes in pretty close.

I believe that the lamps are 3500K.

The screen is 42 inches by 6 inches which is 252 square inches. The new fixture has 12 by 20 watt CFL bulbs for a total of 240 watts of CFL light which (supposedly) is roughly the same as 900 watts of regular lighting or about 14,400 lumens. Version 1 of the fixture had no reflector and had 4 VHOs at 1,000 lumens each for a total of 4,000. The new fixture has ...what... 4 and a half times as much light as the old one, if conversion spec.s can be believed?

{As a side note, my very first ATS used a 300 watt halogen out door flood lamp. I lost a gallon of water per day to evaporation but the water stayed cool. The screen started quickly and grew great algae.}

With the VHOs, I got great growth, two different times, years apart. It started quickly each time. I changed to a more normal fixture of four long "U" shaped compact florescent bulbs because it was less bulky and better looking. The algae continued to grow quite well.

To recap, then I added the bacteria sump and the ATS stopped producing algae. Now it won't restart. I disconnected the sump and removed a good bit of the phosphate and still, no filamentous algae.

I feed about two cubes per day plus a couple of pinches of powder. I ran out of phyto concentrate but normally add 2 ml(s) per day as well. I will get some more this Wednesday.

My feeding changes from time to time, up or down but I normally feed every day. I use to feed more powders because the cube were not as available. I lean toward the heavy side but sometimes I don't feed at all. I usually get about the same results.

As far as the leaching of phosphates, I was/am afraid of phosphates coming back. As you can see, the P and N are doing OK, so far. Oh, another side note: As soon as the phosphate went down, I got about a quarter inch of brownish growth on the rock but it comes of with the turbulence of a waving hand.

I hope this fills in some gaps.

 

[JohnnyB in SD]

I'm no expert, but I would suspect a lack of nutrients in proportion to the effective growing area. Zero nitrates means they are being consumed by whatever is using them. As you say, "export is export". So in that respect, you've got an effective scrubber, even though it's not growing the type of algae you desire.

Instead of increasing nutrient input, reducing the filtering capacity by cutting the light in half as you are doing is a better course of action. But rather than simply taking 6 bulbs out and reducing intensity over the whole area, consider concentrating the remaining 6 over half of the growing area, or about 125sq in. According to mainstream feeding & sizing guidelines, 125sqin of one sided lighting is more in line with the barely over 2 cubes going into the system.

Confirm the temp of those bulbs. 2700K is most effective, 3500K should be fine. 5000K or higher probably won't get what you're looking for.
Shouldn't have more than 90 days usage on them. I switch mine out at 45 as that's typically when I see green dropping off and red/brown increase.
Hope this is helpful.