Algae Scrubber Basics

Thanks Floyd,
I already tried increasing light intensity to 75% in the 600g system but some of the algae bleaches in one of the sides of the screen so I reduced it to 50% again.

now I am leds are on 18 hours a day at 50% intensity

please look at the following photos of the 2 sides of the same screen, when I had it at 75%

75% intensity side 1.jpg

75% intensity side 2.jpg

should I increase intensity and decrease the hours??

thanks again
 
It kind of looks like you have a flow issue, but at the same time that yellow growth would indicate low nutrients + too much light...hmmmm.....

Well there is this thought process too: the yellow algae occurs (generally) when you have too much light compared to delivered nutrients. So the answer is usually, deliver more nutrients (increase flow or feed more, I prefer the former) or reduce light.

However, if you get decent overall growth at a given level (50%) then you can run that level for a longer period of time and you should be OK as this maintains the same rate of intensity (to get all techy, photons per unit time) so you have the same adsorption rate, just for a longer time. This would tend to cause an overall nutrient level drop but it's over a longer period of time, instead of being more instantaneous. If that makes sense. If you were running 14 hrs/day and then 18 hrs/day and growth maintained, this is why. So in theory you can run 24/7 at that intensity and you shouldn't get yellow. Then you can increase intensity in smaller increments and see where your "yellowing" point is, and stay below that.

What's you N in that 600?

N and P in that 150?
 
Thanks Floyd
N and P numbers are:
600g system: N= 2.5ppm P=0
150g system: N= 20ppm P=13ppm

In 600g system I have also tried more time at 50% intensity and I also get a some yellow. in one side.
your flow recomendation makes sense. I already increased the flow in the ATS of the 600g system. with this increment if flow should I increase the intensity of the leds or increase the time leds are on and remain at 50% intensity?

what happens if I increase the flow to much??
I ask becuase even I increased I still can open completelly the valve of ats

2.- the 150g ats is growing very nice and I have it at 100% intenisity 24/7 and nutrients are still high. would it make sense to increase the flow in that one also? if so how much more?

thanks
 
yeah you probably already told me all of this earlier in the thread too right?? I can't keep it all straight!

Anyways...

If you have already had yellowing with extra time, then it sounds like you are already hovering on the edge. Keep in mind that one section of yellow isn't the same as all yellow, it's not horrible to have a few streaks of yellow. I would increase the flow a little bit, and monitor for a week to see if you have any changes in growth. If everything looks OK, add hours and check again in a week.

On the 150, you can increase flow there as well. Also with the growth type you are getting, you can probably let that grow longer (more days) before harvesting. That type of growth, you can usually let it fill up the growth chamber nearly completely before harvesting it and you won't have any die-off (or very little). When the growth chamber starts to fill up with water, that's not clogging of the drain, that's the 3D growth trapping the water. It's still draining...I let mine fill up until the waterline is a little less than 1" from the slot pipe cutout...and I let it sit there for days actually, the first time you do that it's kinda freaky
 
Thanks Floyd.

What happens if you increase the flow to much?
What would be the usual effect in algae growth??

2.- in conclusion in the 600g. I should increase the flow and monitor the algae growth in one week. but I should keep time and intensity as it is now? or should I increase intensity given that more flow = more nutrients, thus ats should be able to support extra light?

thanks
 
There is apparently a limit to the max flow, that seems to be about 50 GPH/in or in that range roughly. After that point, the growth doesn't seem to benefit and actually it might hurt.

Originally the thought was the more flow, the better. This is not always true - again, everyone's conditions are different, so while one person might be able to run happily at 100 GPH/in (I've actually seen that) another may find that 25 GPH/in works best for them.

This is why I backed off on recommending higher flow in general, and why I also backed off on telling people they "must have" 35 GPH/in. While that still seems to be the ideal flow point to get good growth for the majority of people, initially all you need is good even coverage and you can typically achieve this with less flow (in fact, 35 GPH/in initially can result in arcing of flow across the screen).

I've seen plenty of "under-flow" scrubbers with good results. This is what is great about scrubbers - you can adapt things to your need.

The trouble is a) finding that ideal point and b) staying there. The point can shift over time as your tank grows and/or as the scrubber matures.

So that's the long answer to
What happens if you increase the flow to much?
Click to expand...

For this one:

What would be the usual effect in algae growth??
Click to expand...

usually you would see an increase in growth, or a shift in the type of growth.

2.- in conclusion in the 600g. I should increase the flow and monitor the algae growth in one week. but I should keep time and intensity as it is now?
Click to expand...

I would change one thing at a time: increase flow, and change nothing else for a week. Confirm that flow increase does not adversely affect growth (it shouldn't, as long as it's not drastic)

Then, after a week, bump the light intensity up just a bit and confirm again.

or should I increase intensity given that more flow = more nutrients, thus ats should be able to support extra light?
Click to expand...
This is what should be the case, but yours is acting oddly so this is why it's a one-step-at-a-time situation IMO
 
Could be. If it was growing GHA before then shifted to that yellow gooey growth, that generally is an indicator of too much light compared to the nutrients delivered. So did you notice a drop in nutrients or a cleaning-up (out-competing) of DT algae prior to this?
 
Floyd R Turbo said:
Could be. If it was growing GHA before then shifted to that yellow gooey growth, that generally is an indicator of too much light compared to the nutrients delivered. So did you notice a drop in nutrients or a cleaning-up (out-competing) of DT algae prior to this?
Click to expand...
Hi Floyd,

No, nutrients didn't drop unfortunately.. I changed my gfo though, so maybe that did it.. What should I do at this point?

from note 7
 
If it was a large amount of GFO, that could explain it. GFO is very fast-acting, especially when it's fresh. I'm not sure that I would change anything at this point, except to maybe clean the yellow algae off a little sooner in order to keep it from shading the screen. Then monitor to see if the GHA starts to come back after the GFO gets partially depleted.

If the scrubber is doing a good job of keeping phosphate at bay, you might consider reducing the amount of GFO you use and changing it more frequently to avoid a large downward-spiking of phosphate when you change it out, i.e. keep it more stable. I'm not against use of GFO in general, but when you use it in combination with an effective scrubber, it's a bit of a balancing act.
 
Floyd R Turbo said:
There is apparently a limit to the max flow, that seems to be about 50 GPH/in or in that range roughly. After that point, the growth doesn't seem to benefit and actually it might hurt.

Originally the thought was the more flow, the better. This is not always true - again, everyone's conditions are different, so while one person might be able to run happily at 100 GPH/in (I've actually seen that) another may find that 25 GPH/in works best for them.

This is why I backed off on recommending higher flow in general, and why I also backed off on telling people they "must have" 35 GPH/in. While that still seems to be the ideal flow point to get good growth for the majority of people, initially all you need is good even coverage and you can typically achieve this with less flow (in fact, 35 GPH/in initially can result in arcing of flow across the screen).

Thanks a lot

I've seen plenty of "under-flow" scrubbers with good results. This is what is great about scrubbers - you can adapt things to your need.

The trouble is a) finding that ideal point and b) staying there. The point can shift over time as your tank grows and/or as the scrubber matures.

So that's the long answer to


For this one:



usually you would see an increase in growth, or a shift in the type of growth.



I would change one thing at a time: increase flow, and change nothing else for a week. Confirm that flow increase does not adversely affect growth (it shouldn't, as long as it's not drastic)

Then, after a week, bump the light intensity up just a bit and confirm again.


This is what should be the case, but yours is acting oddly so this is why it's a one-step-at-a-time situation IMO
Click to expand...
 


I also cleaned the turf scrubber for the first time. So this is about 2 weeks of growth I guess. There is really not much of a bioload on here yet either. Just a few cubes per day (or less) since I only feed the anemone tank every now and then. But the tank is just finishing up it's cycle, so I suppose this could be normal?



Sump kind of reminds me of a dance club.



I also measured the ATS flow with the screen installed. On a 20" long 1/8" gap with screen inserted into slot, it filled a 2 gallon rubbermaid (to the mark), in 20 seconds on average. So this says only 360gph, or only 18gph per inch. I'm not getting the 35gph suggesion in this case... not sure if there is a problem here or not. Perhaps the slot is closing up a bit because of the length? Or screen inserted too far? This was after a cleaning session/groove scrubbed.



I made some DIY light blockers, paint is still drying. This will be for the ATS to keep light out of the groove.
 
zachtos that's excellent growth for the conditions you have (low bioload, new screen, etc)!

I wouldn't worry too terribly about the flow, I've somewhat backed of on the 35 GPH/in being a hard rule, it's good to have better flow but at least initially, lower flow can actually be better in some cases. Mainly this has to do with avoiding arcing on a new screen (this is less of an issue as the screen matures, so it can handle additional flow without arcing)

See this post on previous page for an explanation of that http://www.reefcentral.com/forums/showthread.php?p=24755780#post24755780
 
Floyd R Turbo said:
zachtos that's excellent growth for the conditions you have (low bioload, new screen, etc)!

I wouldn't worry too terribly about the flow, I've somewhat backed of on the 35 GPH/in being a hard rule, it's good to have better flow but at least initially, lower flow can actually be better in some cases. Mainly this has to do with avoiding arcing on a new screen (this is less of an issue as the screen matures, so it can handle additional flow without arcing)

See this post on previous page for an explanation of that http://www.reefcentral.com/forums/showthread.php?p=24755780#post24755780
Click to expand...

OK, I am pretty sure it is from the groove being pinched from a long 20" cut. I can widen it in the middle a bit I suppose if needed. It is a very low trickle in the center and fairly good stream on the ends on 3" both side.
 
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