Zero turf scrubber growth. Any ideas?

Murraydar · Mar 25, 2020

Been using a turf scrubber for a year or two now. Since about a month ago it has stopped growing almost altogether, and I cannot figure out why. I have a couple tiny bits of ulva intestinalles on the screen thats it. Usually that stuff grows like crazy.

Tank specs:
- 78f
- Calcium 460
- Kh 8.5
- Mg 1400
- Sg 1.026
- No3 ~20ppm
- Po4 .14ppm

My nutrients are elevated, mostly because it stopped growing. My po4 crept up to .3 ppm before I added some gfo.

The screen gets plenty of flow and I have very intense led lighting on it, think it's a 200w grow light running 18 hours on and 6 off. I don't believe these are the issue as it had been growing like a monster for quite a while under these conditions.

I'm thinking I might be limited in an element. Can't be nitrates of phosphates, and I started dosing iron (fergon) about a week ago but I haven't seen any changes.

Any ideas are appreciated. Thanks!

Cory · Mar 25, 2020

Other things are manganese, and zinc. Possibly potassium. You can also try a water change. Are your test kits expired?

Murraydar · Mar 25, 2020

Cory said:
Other things are manganese, and zinc. Possibly potassium. You can also try a water change. Are your test kits expired?

Nah they're all relatively new. I thought about potassium, I'll look into it a bit.

Cory · Mar 26, 2020

I have ulva too and it started taking off with manganese doses. Not intestinalis but true ulva lettuce. Ulva lactuca. I just bough some pills from the pharmacy and shaved a bit in the tank daily. Like dust is all it takes.

Cory · Mar 26, 2020

Maybe it needs more darkness? Are you dosing limewater?

vetteguy53081 · Mar 26, 2020

Iron and good lighting required for good growth and production of algae

KrisReef · Mar 26, 2020

Time for a new light. Everything else seems to be in order for an algae bloom.

Cory · Mar 26, 2020

Fwiw ive been experimenting with a vinegar/sugar mix im dosing. I noticed significantly reduced growth when carbon dosing. Are you? Ive stopped dosing now due to shrinking discosoma mushrooms and growth is getting better again despite high no3 and po4.

Murraydar · Mar 26, 2020

No carbon dosing of any sort. I haven't tested my magnesium in a while but im planning on doing some water changes to see if I can replenish any missing elements.

And the lights are relatively new LEDs, very high wattage grow lights. I might mess with the on off cycle a bit to see if that helps.

Cory · Mar 26, 2020

Murraydar said:
No carbon dosing of any sort. I haven't tested my magnesium in a while but im planning on doing some water changes to see if I can replenish any missing elements.

And the lights are relatively new LEDs, very high wattage grow lights. I might mess with the on off cycle a bit to see if that helps.

Not magnesium but managanese

homer1475 · Mar 26, 2020

Pics of setup?

200W of lighting seems awfully strong.

I have a waterfall type scrubber and only run 2 20W lights on mine and I grow algae by the bucket full.

Cleaned the screen to clean and now your getting burn off from the lights? You definitely have adequate nutrients to grow algae. Or perhaps you cleaned the screen too clean, and now the amount of water going over the screen isn't allowing the algae to attach?

I really have no idea, just some things I've personally done with my scrubber and why it stopped producing.