PO4 climbing faster than scrubber

[b4tn]

Recently my P has started climbing. I have no nuisance algae probably due to a heavy cleanup crew. I had been running my L2 at about 50% (3:00) on the light dial for 10 hours. When I noticed my P climbing I went ahead and started increasing the light schedule a couple hours every few days. To see if I could get the scrubber to catch up. I’m up to 16 hours of light now and I turned up my light to 75% (2:00ish) yesterday and tested again today. P was up a notch and approaching .4ppm. I went ahead and dropped a 1/4 cup of phoguard in the sump in a media bag. And will test again tomorrow morning. How long will light and schedule adjustments take to take affect? Any suggestions?

 

[Turbo's Aquatics]

What kind of food are you feeding? Any coral-only food?

What are nitrates at?

 

[b4tn]

I measure the same amount of food twice daily. A pinch of new life spectrum flake and 1/4 teaspoon of new life spectrum pellets. Once a week I feed a cube of frozen and twice a week 1/4 sheet of nori. I have not tested nitrate today but yesterday it was somewhere between 16-18 ppm.

 

[Turbo's Aquatics]

I'm leaning toward extending hours more, at least for a short period of time. But, a few more questions:

How often do you harvest?

What you do, how aggressively do you clean?

How long since last harvest?

 

[b4tn]

I have been going about 2 weeks between harvesting. The screen is growing a mix of what I think is valonia and turf. It’s the strangest bubble algae though because it’s elongated I assume from the flow. It pops when you scrape or cut it. I get good 3D growth but it peels easily off to bare screen so I have been trimming it with scissors instead of scraping. Last harvest was On the 12th. Pics are from just now.

 

[ReeferSpot]

What size tank?

 

[b4tn]

Tank is a 75 gallon with a 40 gallon sump. Maybe 100 pounds of live rock.
I just checked my journal.
On the 12th
PO4 was .16/.2 and I went from 10 to 12 hours
On the 16th
PO4 was still .16/.2 so I increased schedule to 14 hours.
On the 19th
PO4 was .2/.36 so I increased the light to from 3:00 to 2:00

today PO4 was .36/.4 so I threw in some phosguard.

i should also mention it’s a fairly new setup maybe 5 months old since I moved.

 

[Turbo's Aquatics]

It’s the strangest bubble algae though because it’s elongated I assume from the flow. It pops when you scrape or cut it.

That looks like green turf algae to me, it does sort of "pop" like you mentioned, but it's not bubble algae. It's not a very common type of growth, but it's not a negative.

Instead of cutting it, I would scrape in vertical lines on opposite sides so that only one side of the screen is exposed. Do this once a week so that you are clearing the entire screen every 2 weeks, just breaking it up into 2 cleanings if that makes sense. The idea here is that if cleaning the screen every 2 weeks leaves it bare, that means the algae is blocking light and it takes longer to recover; during this time you might have a nutrient increase and it's constantly playing catch-up

Increasing the intensity right after a full harvest might extend this period a bit if the screen is bare after harvest. Leaving the intensity at a higher point (where it was already pre-harvest) is the same situation. But, if you leave half (approximately) of the algae in place, you can run the lights more aggressively. So in addition to the partial harvests, I would leave the intensity where you have it and run a longer photoperiod - go to 20 hours.

Continue to monitor levels. The Phosgard may throw things off a bit, but it shouldn't matter in the long run. Having it in a media bag loose in the sump will have a more subtle effect than putting it in a media reactor or something with strong direct flow. If you notice a sharp drop in phosphates, you might re-position the Phosgard to be in a location of lower flow (or remove it). Phosphate is one of those things where it's more important to maintain stability versus just a low level - more important when you have corals that are sensitive to rapid phosphate level changes.

 

[b4tn]

Thanks Bud. Tomorrow is water change day I will increase to 20 hours tonight and clean half the screen tomorrow before my water change. I didn’t plan on leaving the phosguard in the system. I more wanted to see if I could drop the P a bit and see if the scrubber would hold it steady. I will probably remove it tomorrow when I do my weekly water change.

 

[DarthSimon]

I second running the gfo in a media reactor. Much more effective.

 

[Turbo's Aquatics]

I second running the gfo in a media reactor. Much more effective.

I was actually recommending not doing this

Having it in a media bag loose in the sump will have a more subtle effect than putting it in a media reactor or something with strong direct flow.

If you want to rely on phosphate media as the primary form of reduction, then yes. But the purpose of running an algae scrubber is to regulate this with a more natural process, and using an aggressive reduction media can interfere with scrubber growth. I recommend using media in a bag outside of a high flow area as means to "take the edge off" phosphate levels when they climb above a level you are comfortable with. Basically, now @b4tn is doing it

 

[DarthSimon]

Sorry, misunderstood what you said above. Honestly I have always had more success having the gfo slowly tumbling in a media reactor, then a bag.

I have a 300g system, and have a turf scrubber and run gfo. Phosphates are .03 to .10 range.

 

[b4tn]

I did the half screen scrape and broke out the macro lens clip on for my phone instead of cutting I scrapped the screen and this is what I meant by bare screen. It’s attached enough to hold on but peels off easily. I also a took a close up of the other side of the screen I didn’t scrape. If you zoom in it’s a massive field of bubbles. I did have a bubble algae problem in my last tank and have a fox face in the display now so I never see it up top.

 

[b4tn]

Sorry, misunderstood what you said above. Honestly I have always had more success having the gfo slowly tumbling in a media reactor, then a bag.

I have a 300g system, and have a turf scrubber and run gfo. Phosphates are .03 to .10 range.

@DarthSimon I’m a firm believer that with a properly sized scrubber once adjusted should be able to handle all N and P issues without media. I have had my turbo aquatics scrubber since 2016 and until recently I just tossed it in the system, set it generally, and let it run. Running like this it stripped all my nutrients to 0. This reboot of my tank I am more fine tuning it so that I can get the exact levels I want. The issue here is as I’m adjusting it slowly I think it got behind. As mentioned I threw some phosguard in a media bag to take the edge off while i figure out why it’s not catching up.

 

[DarthSimon]

So I would love to achieve that. I have a scrubber that’s rated for a 300 gallon system. I run the lights on mine 20 hours a day. I would say I scrape it every 14 days or so. How can I fine tune it?

I still find I have to run gfo to achieve low phosphates .

 

[b4tn]

@Turbo's Aquatics Bud feel free to jump in and correct me if I am wrong. I’m not sure what scrubber you are running but I think the key to a successful scrubber is light and flow. When I was shopping for scrubbers there where not many options but turbo aquatics IMO was and still is the best scrubber on the market. Bud put a lot of thought into the design and even to this day reaches out to his customer base for recommendations on refinement. His scrubbers are all hand made so there is a bit of a wait but it’s worth it for the removable chamber, invincible slot tube, dual overflow, cemented screen, false chamber bottom, etc. just the little details.

To answer your question though the adjustability comes in the light. The light on this scrubber is very intense, the proper spectrum, about an inch from both sides of the screen, fully enclosed, and the intensity is adjustable. Light is the prime source for sucking out the nutrients so as the screen matures you can increase the intensity for more growth and then further fine tune it by increasing and decreasing the length of exposure time. I am also putting 250-300 gph across the screen.

My previous scrubber wis a DIY type with a large screen, one sided screen with a par38 bulb. It worked but I still had to run gfo, it was noisy, it splashed a lot, was a pain to clean, and light spill made a mess in the sump.

 

[Turbo's Aquatics]

You pretty much got most of it. The lights are about 1" from the outside of the growth chamber, but about 2-2.25" from the screen itself. When there's a ton of growth though, that's where the lights are 1" from the growth (inside of growth chamber) so you're not wrong.

The only thing I would add is that my growth chamber is designed to be a specific width in order to encourage the algae to "pile up" on top of the false bottom and trap water, getting you that 3D growth. As a result, the algae will tend to self-support, and what I've found is that this then results in the algae relying less on anchoring to the screen - I rarely use effort when scraping my screen, just a pass or two with the scraper and it's good to go (and it takes less time, but we're talking seconds).

I had several people complain when I went from Rev 1 to Rev 2 because people with big hands couldn't get into the box to clean it very well. The removable growth chamber was part of my solution to that problem, without having to compromise the narrow chamber method - because as irrelevant as most would think that dimension matters, it actually makes a major difference.

 

[b4tn]

Here is a week update. I upped the hours to 20 still around 75% intensity. Phosphate was approaching .4 but the combination of phosban, water change, and cranking up the scrubber I am sitting closer to .16/.2 range. I tested daily this past week and it has not gone up beyond this point staying pretty stable. Here is the growth I got from one week after scraping the screen bare. I only scraped the left side last week as recomended.

I scraped the side I let go for 2 weeks down to this point and harvested a large handful

 

[b4tn]

@Turbo's Aquatics so scrubber has been running 22 hours with the light knob set where it’s at in the picture for several weeks now. The screen pictured is 1 weeks worth of growth. I am not getting a spike in N and P after harvest so I have been cleaning both sides of the screen every two weeks or so. My display is pristine algae wise. I do get a dusting on the front glass every few days and that’s about it. But I can’t get my phosphate down below .2 and nitrate below 16-18. If I run 1/3 cup of phosguard in the filter sock I can get it down to .15 but have to change it every few days. I know I “could” put in the reactor to get it lower but I don’t really want to run any GFO products if I don’t have to. So the question is should I go to 24 hours of light and raise the light intensity to 100% I really don’t feel like I’m feeding that much and have verified phosphate results with 2 test kits (red sea an NYOS) I’m shooting for .05-.08 phosphate and 5-10 nitrate

 

[atoll]

I also have one of Buds Turbo scrubbers and believe it's the best out there not that I have tested them all but not just on growth alone.
I griw Ulva intestinalis and have to harvest at least ever 5 days often 4. Because my scrubber is around 4/5 years old and under powered for the amount of food I feed each day I not only replaced all the LEDs but put an extra 4 on each side hence why I have to harvest as much as I need to.