Quantifying Biomass

[Floyd R Turbo]

I weighed my harvest from the doc's tank today, 14 days growth (all green, no dead roots!). Forgot to bring scale and squeezing equipment so I bagged it and took it home. Using my digital scale and subtracting the bag weight it was around 233g wet and 70g dry/squeezed.

I squeezed it first using an old hang-on QT tank / birthing trap thing, a piece of mesh, paper towel, and a water bottle with a squarish bottom to squeeze it out. After a few minutes I had an algae pancake. But I was able to squeeze a little more out with my hands, but not all might be able to do so, this algae is nice and all GHA no slime, at all.

Addition:

so that's 70g / 14 days = 5 grams/day over 24 sq in = 0.208 grams per day per square inch, but that's LxW so if you count surface area (LxW x2) it's half that, or 0.104 grams per day per square inch.

[Floyd R Turbo]

I just reviewed Garf's first post and I'm getting a little under 50% of his g/sqin/d harvest, but that's squeezed/dry weight. If I used the drip-dry weight of 233g, that's 233/14/48 = 0.346! Take that!

[Garf]

I just reviewed Garf's first post and I'm getting a little under 50% of his g/sqin/d harvest, but that's squeezed/dry weight. If I used the drip-dry weight of 233g, that's 233/14/48 = 0.346! Take that!

Yeah, I think my single sided cleaning may be skewing the comparisons a bit. I've included the area of both sides in the calculation but actual only harvesting half of the area every 9 days.

edit - but then again, the harvested side is 18 days, so probably evens itself out. I've gotta get my figure up. Ditching the worn out cfl's first. Also gonna harvest more regularly.

[Ace25]

Ace, what is going on in your tank that your scrubber can't beat that out?

Million dollar question, I wish I had the answer. I know the deep sand bed in that tank is one of the factors causing my issues. I have tried numerous things to resolve the issue (taking out sand/cleaning/baking it, and 'cooking' the rocks) but all my fixes seem to only last a month tops and then the algae grows back in force. I have major plans for redoing that tank, actually, had those plans for the last 2 years, just never seem to find the time to get er done. I know it is going to take 2 full days to redo the tank from scratch and my biggest fear is my delicate fish. They will have to be put in holding tanks during that time.

Right now I have a new ATS design in my head that I hope to build soon, one that I hope can solve most of the issues we talk about on here. It won't be a surge system due to the complexity of that, but it will have multiple screens and a new way to mount them and deliver water to the screen (not a pipe/slot method). It will be 4 small screens, 6"x6", and dual chambered (middle will have LEDs facing both directions), that way I can remove 1 or 2 screens at a time to clean and still have 2 screens in place in order to not shock the system at cleaning time, just to give you some idea of the direction I am going.

I don't know how much the 'biomass' question plays into the health of a system because the system I have with all the algae problems in the display has grown at least 5x more algae per week on the screen for the past 4 years, while my other system I can go a month before cleaning and still can never come close to the amount I clean from the 75G system in a week, yet, that tank is doing 1000x better, no real display algae problem and corals are doing good. I think it just falls under the 'every tank is different' mentality (even though I used the same rocks/sand from my 75G when I setup the 60G).

[Garf]

Tried the squeezing technique and started at 295 grammes (this side is 100 sq inch, 9 days 2 x crap cfl's + 4 days LED growlight). After vigorous squeezing could only get it down to 155 grammes. So perhaps my dense carpet of algae holds a bit more comparative mass. Anyway, the calculations for this would be 155/13/100 so 0.119 compared to Floyds 0.104. However, that's trying to account for the fact I'm cleaning only one side at a time ie. the screen size figure of 100 is only half of the actual screen size. These figures may be more useful when tinkering with individual systems, rather than comparing different systems as we know, all systems tend to run slightly differently.

[Floyd R Turbo]

I weighed my harvest from the doc's tank today, 14 days growth (all green, no dead roots!). Forgot to bring scale and squeezing equipment so I bagged it and took it home. Using my digital scale and subtracting the bag weight it was around 233g wet and 70g dry/squeezed.

Addition:

so that's 70g / 14 days = 5 grams/day over 24 sq in = 0.208 grams per day per square inch, but that's LxW so if you count surface area (LxW x2) it's half that, or 0.104 grams per day per square inch.

Weighed the harvest again today: 16 days of growth, I removed one diffuser (Rev 1 L2) and about 1/2 way through the growth period, I had to remove the pump to move a Flame Hawk that likes to go to the sump, so I rinsed out the pump (wasn't really that dirty).

The result was a wet weight of 349 grams, dry/squeezed weight of 121 grams

Addition:

121g / 16 days = 7.5625 g/d over 24 sq in = 0.315 g/d/sqin, but converting to physical area (48 sqin) then it's 0.157 g/d/sqin

That's a 50% increase in harvest! Woo hoo!

[Garf]

I'm gonna keep the shorter cleaning period for a while and compare growth with new harvests, now my cfl's have been changed (about 7 months old). I like this method of quantifying mass. The algae on the last cleaning seemed to be more watery than I'm used to.

[Garf]

G.H.O.S.T. screen, second cleaning harvest of cfl powered side (probably 20% of guideline lighting);

10 grammes squeezed, 65 sq in, 7 days is 0.022g/I/day

[Floyd R Turbo]

Harvested the scrubber from the Doc's tank today - 17 days, 100g even

100g / 17d = 5.88 / 24 = 0.245g/d/sqin, /48 = 1.23g/d/sqin

[Garf]

Waterfall screen;

190g squeezed, 20 days, 100sq inch = 0.095g/day/sq inch. That's nearly three times the average growth that this screen produces when cleaned every 7 days.

Ive also saved the harvest to do a dry weight test at work (with high accuracy scales and a proper drying oven).