I agree..... I have almost always had > current than conventional wisdom dictates for my size tank at the time and have never had issues.....

You can see when they get tired, they just drift into a quieter area.

My fish like to swim against current and then RIDE the current back to other side and start over in a loop.....they do this for hours and fish join/leave as desired.

I did some reserach on the Mazzei venturi.

Question:

Where in the flow is this placed?

Thanks,



conventional wisdom BTW is somewhat of an oxymoron, like 'government intelligence' , but don't get me started on THAT thread lol........

G-
You place the mazzi many places, depends on if you want the mist of the dissolved CO2 effects.
Generally folks add it near the top of the return line and they make a Tee off the main line with some ball valves to throttle flow in/out of the mazzi loop.

You can adjust it so that you get more/less mist to suit.
I like mist, think it really makes the tank pearl well and keeps things clean and perky.

But it's nice to do this, and then for photo's, stop and adjust it.

Regards,
Tom Barr

I see the reason now and at least you have the ball valve if necessary.

[/quote]2. I do get good pearling within 1-2 hours of lights on and it is very obvious, so the DC color is not as important to me, as the other visual clues as per Tom's earlier response. Tank is very healthy.......[/quote]

This is a little different for me regarding the pearling, I get little to no pearling at all and I have lots of mist around but as Tom stated { Flow can blow that off while still producing higher growth rates, thus you cannot tell as easily.}. I often wondered if this was possible even though my DC was blue but now I have confirmation that high flow and misting still gives plants needed Co2. I must say having a lower flow versus higer shows a ridiculous difference with pearling and like you with the higer flow, the lower flow is giving me great results, plants are happy and I have no algae.


I see you're tank is more in tune for your fish while mine is more plant oriented so more flow is in your best interest.

It is interesting to note that Tom apparently uses 2 pumps in his setup, one for overall turnover ' the sump' and the internal flowrate 'canister & UV on closed loop'. Still a big difference in my eyes as his co2 gets circulated in his tank longer 'max contact time' even though he is @ 1600GPH...sounds efficient don't you think?



It is placed on the return line, I woul dthink closer to the pump as possible.

Yes, the idea I have is FASTER current, turnover times, more responsive CO2.

I really do not care much about the little I lose to some surface movements, so what?
As long as the surface is not breaking, I'm fine.

I have a wet/dry, but the over flow box is sealed, as is the dry part of the box, no CO2 can escape there.

If you have high fish loads, it pays to have high flow rates, if your fish loads are small to moderate etc, then you can definitely get away with less, but not too little.

The problem here is the plant biomass, structure of the layout and the flow rates/patterns in the tank used to make comparisons, I'd suspect they are quite different for each tank we are discussing.

By being able to adjust things later, we can change them to optimize the tank for both plants and fish.

I use to be 100% plant, but the last 3-4 years I've moved back to center and focused more on the first love I had in this hobby: fish. So I weigh the fish and plants equally, this works well also. Same with methods, I weigh non CO2 and CO2 methods the same. Reef vs macro algae and so on.

Now, back to the topic at hand here, the DIY venturi method.



Regards,
Tom Barr

I saw in the previous post that the PVC you used in your example was 1ft long. For my 72g should I cut the two foot piece down to a foot or 18" or is the height largely irrelevant?

Unless you are really pushing higher flows than say 400gph through there, 12" should do it.

Regards,
Tom Barr

Count me as another believer in your reactor. Per your suggestion I purchased a 300gph pump to power, ran the outflow to my main 500gph pump in my sump. I'm not entirely sure about the venturi, but I simply looped from the reactor to the pump output. Is this effective enough? I do get a small occasional mist of bubbles, most of the time there is nothing to see.

It works fast, (I have my CO2 timed with my lights) within an hour all plants (except the lowlight plants) in my tank are pearling, I have a pH drop of about 1 . I might build another reactor as this one has a very small leak between the bushing and coupling, and I put no bioballs in, but even with these caveats it is extremely effective.


Thank you for your help and coming up with this design.

Fred

Fred - sounds like you have it working correctly........I'd be curious if it works better if you use bioballs later.........

This has worked well for my AM 1000 modification as well and was simple to do

My drop checkers both show 6.6 so I can really tell that this works. Nice green color

One thing I noticed and was curious about re: the flow required to drive the reactor.

I came home today and my reactor was almost empty of water.
Only the bottom 1" out of the approx 12" total length contained water. This was NEVER the case previously, but I did recently INCREASE the amount of c02 input.

Turns out an air bubble had formed in the reactor pump and reduced the flow of water to the reactor.

I knew this could happen with a canister (from other threads), but thought that this type of pump was somehow immune (don't ask), but I guess the impeller is right there so I shouldn't be surprised.

ANYHOO...

I removed the venturi loop for a second and eliminated the air bubble and all was fine with the flow......

BUT

The pearling of my tank was HUGELY IMPROVED during this time frame. Pearling occurred within 30 minutes of lights on vs 90 mins prior....and the evidence of pearling from the bottom of the tank was tremendous and overall much increased all over the tank....

1. Was this increased/better pearling caused by the reduced flow in/out of the reactor?

2. If so, should I use a smaller pump to drive the reactor? I use a 500 gph Mag drive to run it now. I would say the flow was reduced by at least 50% during this time frame..........

3. Do I want to somehow have LESS water in the reactor?

I thought that MORE flow to the reactor was better????


BTW, I never thought I would see such levels of c02 with my setup (overflows, wet/dry, etc). Awesome.

Thanks again to all for your advice and patience.

P.S EI after 3 weeks shows a marked improvement in plant growth and health/color. Thanks again!

Mine is working well, even though my DIY skills are weak at best

I am far from an expert as you know, but my guess is, and , I think Tom covered this earlier ,was that the higher flow rate may reduce the appearance of pearling, but the same rate of photosynthesis is taking place, the flow of water itself may drive off some of the O2 bubbles.

Ironically I think one of the main reasons this reactor is so much more effective is increased flow. In tanks the size of ours the advice I received of having these puny powerheads is probably erroneous. I think the increased flow disperses the CO2 throughout the tank much better

Fred

Gerry, during the time that your reactor had the gas pocket, how was your venturi loop functioning? You previously said that you never got the gas buildup in your reactor, and that the loop was only circulating water. When the gas did build up, did you get any misting action with the loop? Was gas flowing through the loop? Getting chopped up? Even if you didn't see any mist in the tank, maybe the co2 was getting recirculated from the reactor via V.Loop and was helping efficiency. Maybe this is why you saw pearling much sooner than when there was no bubble in your reactor?

I would think that if your co2 bubbles were totally dissolved before they exited the reactor, that the reduced flow through the reactor wouldn't be able to increase its efficiency any higher (Before air/gas pocket built up in reactor) It would seem that lower flow would increase contact time with the co2 bubbles, but if the bubbles were previously getting dissolved entirely, that lower flow INSIDE the reactor would serve no purpose. Right? I'm just thinking....
I think a weaker pump driving the reactor would make the water flow through the reactor slower, but wouldn't produce a gas pocket inside it. But I think SOME gas buildup is the point of having/using the venturi loop on the reactor. I wouldn't downgrade your reactor pump, but I also wouldn't release the gas buildup either, or only a little bit - but not the entire "pocket". That way you can take advantage of the gas recirculating through your V. Loop.

Sorry for rambling...I tend to write via "stream of consciousness"

Still, I'm curious as to what your venturi loop was actually doing at this time....

Guh-Bye!
-Mike B-