Algae Scrubber Basics

PWC = partial water change

As for thing done in the past to reduce N, PWCs, skimmer, filter sock, water changes, adding LR

For P reduction, same as above and also limiting dried pellet and careful selection of other prepared food, Brightwell products (can't remember which), RowaPHOS ($$)

Regarding the current P I have done nothing to try to reduce it. I accidentally left the lights on the scrubber on 24/7 and they dropped to 0.03 but then, curiously enough, I had a dino outbreak. Still haven't quite figured out why, but could be related to the screen partially dying when a fish got stuck on the intake pump for a day or two while I was gone, those events were both pretty close to the outbreak. They rebounded to 0.13 in no time. I use RO/DI 0ppm top off so unless by BRS 2-part has Phos in it I'm at a loss. I was going to start adding Calcium Nitrate but decided not to 'cause it ain't broke. The reason for doing that is because algae needs N and P to grow, so in this case N=0.000 (on Salifert) so P is not absorbed, it's called Nitrate Limitation (can happen the other way too and you are then Phosphate limited) and you have to actually add Nitrate to get the P down. lol.

As far as growth, it's not my primary concern. Things grow at a decent pace. The slower the growth, the more dense the coral. Tank is way too crowded as it is!!

 

Ya, N and P are not bound together and it seems a little tough to figure out a good strategy to have both low and provide nutrient export. You can always mop up P, but adding N is not what I want to do. Low N can be done with sand beds and LR, but yo uneed to lower P.... so coming to a balanced approach of LR and algae scrubbing is where I'm at. No different with various carbon dosing. I want a minimal tank, so a tub of LR attached to the system will be necessary.. or at least desirable for other reasons.

Thanks for PWC... obvious after you say it.

And ya, every one want a full tank... until it is full, then it's crowded. But thanks about saying that out loud, never thought of it... slow equals dense... cause I have had cases of my corals growing to flow or what ever and some branching out quickly... not exactly what I wanted. Interesting.

 

There is only one thing holding me back. Is not having crystal clear water. Is that true?? It dose not need to be supper clear but I don't want to look at it and be dang it's yellow??

 

Man, that is such a dated concern. I hear that comment every now and again so it makes me realize that there are still people out there spewing garbage about algae scrubbers (or maybe that was from an old thread) but that comes from cleaning the screen in the tank, which is how it used to be done (and with some horizontal scrubbers where you cannot remove the screen completely, it still is).

I dare you to find a tank running a vertical waterfall scrubber that has even a hint of yellow in it. I pull water out of another non-scrubber tank I maintain and put it in a white bucket and it looks like I urinated in it. I pull water out of the scrubber tank and it looks like freshly mixed saltwater. I am talking crystal clear. See pics of my tank on post #9, then pull up the YouTube videos earlier in this thread of screen cleaning, then go to my channel and you tell me if that water looks yellow.

 

Sure thing I have never seen a tank ran with a vertical ats an the only one I have seen was so new it really hard to tell. What I have read to do was take it off and swish it to get pods in tank then scrape half of it rinse with ROdi water to kill pods and return to tank? What about smell if I clean it weekly - bi-weekly?

 

Probably your best bet at this point would be to spend some time on the algae scrubber site, Algae Scrubbers • Index page. Lots of good information there and will probably answer a lot of questions. There is also a very long thread in the Advanced Topics area on RC if you have a few days to kill, but the summary covers most of what you need to know. The cleaning and maintenance summary (part 2) I don't know if I'll ever get to....

 

My water is much clearer after adding the vertical scrubber. There is actually more science to prove that it clears water than yellows it. Unless the algae strand breaks in the tank you won't get a tint in your water.

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Algae cells will release some organic carbon byproducts when growing. However, my understanding is that the majority of carbon released is due to lysis, predation, parasites etc... So, if the algae is healthy and growing and being harvested before significant tissue turnover starts to occur, then the release of organics should be pretty minimal. Personally, I still like the idea of running the effluent though some, GAC, but whether or not that is necessary depends a lot on the health and maintenance of the system. I'm a believer that GAC should be run anyways though to help remove organic toxins from a variety of sources. When a scrubber is implemented, GAC still acts as GAC, but has the added benefit of insurance in case some excess organic carbon is released from the scrubber. In the end that's sort of a personal preference though.


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So, assuming I understand this correctly, for my 20H setup, if I planned on feeding two cubes per day I would need a minimum of an 8x6 (or 6x8 if it matters) screen? If so then that is awesome, because it means it will be very compact. That also means that I would only need 2 23w bulbs, and 280 or 210gph of flow, meaning a smaller pump. Am I thinking correctly or am i missing somehting?

 

6 x 8 is 48 sq in (dimensional area) so that's a 4 cube/day scrubber. You would only need 6 x 4 , lit on both sides with a total of 24W. Since 23W CFLs are pretty common I would do 2 of those and cut your photo period in half using the high wattage technique.