100 Gallon Mixed Reef GHA Battle

[mstevens]

First of all thanks SM for this great site, it has been very helpful to me.

I have been battling GHA for the better part of 2 years now. I have been running an algae scrubber for about a year and a half, and it has helped, but has yet to eliminate the nuisance algae for good. I believe the scrubbers I have built are not powerful or large enough for my system, but i have a santa monica 100 on order and should arrive within a few weeks. I am going to post the progress of eliminating the GHA after the new scrubber is up and running. My current scrubber is plumbed from my overflow with 2 68w 2700k cfl bulbs (i am experimenting with two on one side in the pics below). I used to harvest lots of GHA on the srubber (and i would still have lots of it in the DT) until recently it seems to be all red turf algae. and now i am having trouble growing that as well. I should also note i used to have tons of pods and those seemed to disappear when i stopped growing green algae on the scrubber and mostly started growing red turf. I am not going to spend too much time with the details of my existing scrubber due to the fact that i have the sm100 on its way.

I guess i am looking for thoughts or suggestions as to why the scrubber stopped producing green algae and pods, and started growing red turf and the pods dissappeared. I should note there are still some amphipods that i find on the screen, but i used to have thousands of copepods and they are now nowhere to be found.

Heres some other useful info:
I feed mostly frozen which i strain through coffee filter once every other day.
20% water change every 2 weeks.
nitrate & phosphate readings been zero for years (probably being consumed by algae on rocks)
sand bed approximately 4 - 5 inches, which i don't disturb (could this be a nitrate factory??)
i only recently (few weeks ago) started blowing off the live rock with a powerhead once a week for detritus buildup.
my flow probably could be better in the tank i have one "dead" spot with no current for sure.
120 - 150 lbs of live rock.

[attachment=2:2zn4uz4q]100 gallon reef.jpg[/attachment:2zn4uz4q]

[attachment=1:2zn4uz4q]GHA.jpg[/attachment:2zn4uz4q]

[attachment=0:2zn4uz4q]scrubber.jpg[/attachment:2zn4uz4q]

[mstevens]

Heres another pic of the screen. 4 days after cleaning and not much growth.

[SantaMonica]

but has yet to eliminate the nuisance algae for good

Definitely a sign of a weak (or improperly run) scrubber.


2 68w 2700k cfl bulbs

Without reflectors, you are losing half the wattage from the start. So now you are down to 68 watts total, and that's when the bulbs are new.


i am experimenting with two on one side in the pics below.

Never good. You never want a dark side if you can help it. Dark or low-light areas (the other side of the screen) do not filter much at all.


I used to harvest lots of GHA on the srubber

I'll tell you what happened in a second.


I am not going to spend too much time with the details of my existing scrubber

A lot of this will apply to your new one too.


I guess i am looking for thoughts or suggestions as to why the scrubber stopped producing green algae

Because (I bet) you have not replaced the bulb in the last 3 months. This lets turf takes over, which is not a good filter (grows too slow; blocks light from screen). You'll still get turf when you have GHA, but you need to scrape the turf off with a hack saw blade.


the pods dissappeared.

Don't know about this one. You always should have the tiny white dust specs in the water. Maybe they don't grow well in turf.


I feed mostly frozen which i strain through coffee filter once every other day.

No need to strain... the small particles are great coral food.


20% water change every 2 weeks.

Won't help (as you have seen).


nitrate & phosphate readings been zero for years (probably being consumed by algae on rocks)

Yes, due to weak scrubber.


sand bed approximately 4 - 5 inches

DSB's are not that strong of a filter (as you have seen).


could this be a nitrate factory??

Nitrate is better than ammonia.


i only recently (few weeks ago) started blowing off the live rock with a powerhead once a week for detritus buildup.

Won't help the nutrients. It's still in the water, decaying, which is a good thing for the corals because they love it.


my flow probably could be better in the tank i have one "dead" spot with no current for sure.

As long a some animal (at least one shrimp) can go eat it and break it up, it doesn't matter. Besides, it's still in the water.

Looks like a classic case of not replacing the bulb(s) for, I'll guess... one year. And, not removing the turf before it builds up. Solution: Get everything off of the screen, get two new bulbs (one on each side) with reflectors, and scrape the turf when it tries to grow.

Or just wait for your new one :)

[mstevens]

Thanks alot for the reply. I always felt the need for more power and/or reflectors for the lights. I am just limited on space and didnt want to build an unsightly external scrubber. Which is why i was really excited when i saw the sm100. It looks really slick.

I appreciate the answers it helps a great deal.

thanks.

[SantaMonica]

What about the bulb replacement?

[mstevens]

What about the bulb replacement?
The last time i replaced them was about 9 months ago. I did not think the new spiral type cfl bulbs needed replacing as often as they do, but i wasnt thinking along the lines of the light spectrum shifting which is what im guessing is going on?? Or is it the intensity that is changing?

[SantaMonica]

The lumen (and PAR) output of any CFL or fluorescent bulb drop dramatically after 3 months. You can't see it with your eyes, though... you have to use a light meter.

[mstevens]

The lumen (and PAR) output of any CFL or fluorescent bulb drop dramatically after 3 months. You can't see it with your eyes, though... you have to use a light meter.

Thats good to know. Does that apply to the tradition aquarium compact flourescent bulbs as well? I run supplemental actinic bulbs to go along with my MH's.

[SantaMonica]

All fluorescents.