View Single Post
Unread 03/14/2018, 10:09 PM   #973
Floyd R Turbo
Either busy or sleeping
 
Floyd R Turbo's Avatar
 
Join Date: Oct 2009
Location: West Des Moines, IA
Posts: 4,265
Blog Entries: 15
@Twinfallz, you're right and wrong

Excess flow does not seem to benefit much, unless you have the ability to sort of "inject" it into the mat rather than just allowing it to flow over the top. Even then, IMO, it's a marginal improvement

Too little flow can mean slower flow through a larger/thicker algae mat and incremental increases in flow would likely benefit to a certain point.

So there is a point of diminishing returns with relation to flow volume (more accurately, speed)

But I think a focus on a "tank turnover rate" is not a primary concern, but rather something that you just might consider when choosing or designing a scrubber. On a larger tank, a wider scrubber means higher overall flow.

Taken to an extreme, a narrow and very tall scrubber would mean a long pass, lowering the nutrients more on a single pass. But, you have a lower TTR. The result with that scenario compared to a screen with the same area but 4x wider means less contact time but more TTR, so the result over the long term is pretty much the same.

The net effect is that it's pretty much a wash.

Combine that along with lower flow rates in general being relatively effective, TTR is even less of a factor. What I mean by that is that the 35 GPH/in "rule of thumb" IMO is really not a target anymore, it's good to get close to that, but you can still run a quite effective scrubber with a lot less flow. Hitting 35 GPH/in is not going to make or break your scrubber. I've seen examples of great growth with something like 20-25 GPH/in. IMO that 35 GPH/in rule is reduced to a target maximum but not a hard & fast rule by any means.


__________________
Algae Scrubber Basics!!! GOOGLE "algaescrubber zoho"
General Interest Forums --> Advanced Topics --> Algae Scrubber Basics (sticky)
--> POSTS #3251-64 (Basics), #5206 (Cleaning), #6884 (LEDs), #729
Floyd R Turbo is offline   Reply With Quote