Discussion in 'Completed DIY Projects' started by Ed Seeley, 31 Jan 2009.
Oooh getting all excited about this now Can't wait, one more thing out of the tank
Looking really good Ed, I love the journal style documentary of progress.
I may need you to post mine as I can't find any time in the next few weeks that I'd be able to collect, shame that as It'd be great to meet you.
I'm looking at getting a new external filter to run this on in the next week or two so I don't want to have to wait any longer than is necessary and it'd be better to setup both together.
Are you going to pressure test these? I don't mind if you're not and maybe better for all involved if they individually test themselves before fitting. If there's a simple way to test maybe you could advise on how to.
Oh by the way, what was the result in the optimum length of the reactor?
Also, I assume you are going to let us know the answer to the bioballs inclusion and is this an optional extra and will the bioball addition slow the flow rate by much?
Well done Ed.
Looks great Ed, look forward to seeing it in action !
Can you not make it to East Bridgford next Sunday to see Mark's scape? If not we'll sort something out to save posting it I'm sure.
I wasn't going to and there's probably not much point. The only thing I can suggest is that they are ran in a bucket at first just in case, but the amount of silicone and SW I have, or will be using, means it shouldn't be a problem. They won't leak!
No way to test that unless I built a series of reactors of different lengths I'm afraid! I think the way to look at it is that the longer the reactor the more efficient it will be. The 50cm length one I've built still means some microbubbles get through into the tank once the CO2 level in the water gets up to 30ppm. However there aren't many.
I'll do a post on that below.
Having problems posting this at the moment but will persist!!!!
At the moment I have tried this reactor both with and without bioballs in the reactor and made some observations.
The first thing to bear in mind is that I have been testing this reactor with 12mm fittings, not 16mm. This means the water has been entering the reactor at a higher velocity than it should with the larger fittings and therefore I think it is currently working much less efficiently than it will with the larger fittings! This is because the flow from my Ehiem 2128 is being squeezed into 12mm pipe which reduces the overall flow rate but also increases the velocity of the water through that section of the pipework.
My initial observations were that;
Without the bioballs some microbubbles got into the tank once the CO2 levels got higher.
With bioballs it seemed initially that less microbubbles went into the tank but they still did as the CO2 level climbed.
I put this is down to it becoming more difficult for the CO2 to dissolve as the level of CO2 in the water rises which is to be expected.
So what effect did the bioballs have?
With the bioballs in the clear tubing it is clear to see that they create pockets of lower velocity where bubbles linger and collect rather than going straight back into the tank. Indeed bubbles actually collect on the bioballs too within their structure. Bit this doesn't happen to all the bubbles some go straight by.
Also some debris, despite the reactor being after the filter, has collected on the bioballs.
Does this lingering and collecting improve solubility?
Well here I'm not too sure! If bubbles stay in contact with the water longer then they should dissolve more, however these bubbles do not seem to reduce in size when I observed them. Nor do they seem to collect to the size where they bubble back up to the top so I'm really not sure.
Do the bioballs increase resistance in flow?
Well, in a word, no! Well not significantly anyway. The diameter of the reactor means that the frictional head of this section of pipework is significantly lower than the 16mm tubing of the filter. Adding the bioballs in will reduce the cross section but 50mm diameter will have a cross-sectional area of 1963.5mm2 compared to only 201.1mm2 in the 16mm tubing. The bioballs are about 30mm diameter so, even if they were solid they would only reduce the cross-section of the reactor flow area as follows; solid bioball cross section 706.9mm2 so the areas left would be 1256.6mm2 - still significantly above the cross-sectional area of the 16mm tubing and therefore with a potentially lower frictional head than it.
This also means that adding this reactor (as long as you don't increase the length of the tubing or add any sharp, restrictive bends) should have no effect on the head (and therefore flow rate) of the pump.
Are the bioballs worth adding then?
IMO no and I will be removing them from my reactor. The other thing I haven't yet pointed out is that while the water flowing near and around the bioballs is slowed and bubbles lingered there, the water in areas away from the bioballs in that section had to move faster to compensate for these lower flow areas. That meant that some bubbles got whisked out of the reactor more rapidly while some collected amongst the bioballs. Overall I think this would balance out the same as if the reactor was empty.
Well then would a media that filled the rector completely work better?
Possibly, but it will also potentially clog more so I would rule it out. I have some netting from James and was also thinking of trying some coarse foam in a layer to try and see if that prevented microbubbles returning to the tank but both of those would require cleaning at intervals and I don't want to do that!
If any of you who are having reactor want me to put something inside then do get in touch but I think they'll be best empty for all the above reasons.
Good stuff, Ed.
No balls for me bud
Great write up Ed - no balls for me either thanks.
Good conclusions there Ed. I'll keep mine empty (anything that reduces maintenance!)
So true in both counts
just curious as to ruffly what one of these would cost to build, as i'm looking to buy the lunnapet 16/20mm external reactor for 39 euros
Looking very good, it's making me fell lazy just watching!
Like the others i'm happy to go with no bio balls.
These have cost roughly Â£25 plus whatever postage cost to get them to people. However you can only obtain clear PVC pipe in 5m lengths AFAIK.
Thanks everyone for the feedback on the media guys - all empty then so far.
Yep agreed, makes sense to allow the bubbles to rise against the flow and disolve there, without any mass to interfere with the inevitable consequences.
I too am happy without balls
No balls pls.
Well major hitch number... Oh I've lost count and getting rather frustrated now!
The nice metal airline valves leak.
The new ones are a slightly different design to the old one on my reactor and that dripped for a few days then stopped so I assumed it was due to the age of the valve. Looking at the new ones today (before I started drilling the fittings, thank god) I realised they have no rubber or anything to seal them, just metal against metal with a spring to keep them a close fit. This might be ok for an air feed but it's no good for our reactors!
I'm looking at some micro-irrigation fittings that will replace these and, as they're plastic not metal, they will be easier to glue in place. More delays though I'm afraid as I've got to find ones that will do the job and not leak and then fit them and glue the fittings onto the clear pipe.
If anyone has any suggestions to suitable valves then I'd love to hear them; they may be better than the ones i'm looking at now, http://www.lbsgardenwarehouse.co.uk/recno/21/Threaded-Vari-Flow-Valve-PRDWM36/
These might be an alternative, http://www.airlines-pneumatics.co.uk/webcat/Detprod.asp?ProductCode=S0701025
well spotted Ed, at least you hadn't drilled the holes first.
The first ones you listed there are the ones I used on my overflow and on both my CO2 reactors for the drain hose. Work solid for me - no leaks.
Excellent work Ed, I've been watching this closely for some time because I wanted to know if I should remove the netting from my Aquamas reactor.
The Aquamas is about 40cm long, efficiency is much as you describe - I have to push the CO2 right into the lime green before the odd small bubble escaped the reactor. Personally I turn down the CO2 slightly when that happens. I find the netting does trap some bubbles and may chop others up but its not clear if trapped bubbles actually disolve - one wonders if the CO2 dissolves but air replaces it? The netting does not trap dirt and takes several weeks to get slimy with diatoms before it needs a rinse under the tap.
As far as I can tell, flow from my 2028 is not impacted. I am not sure if low flow is better (less chance to wisk bubbles away out of the reactor) or high flow (more water passing for each bubble to dissolve into)?
Is the entry of the bubbles completely silent? Mine goes "plop plop plop".
Cheers Ray. I want to get them done and sent off now as the delays are starting to get on my nerves, never mind the guys waiting for them! I'm sorry to all of you.
There's a slight 'fizz' when a bubble goes in; almost like someone a bit out of breath but very very quietly. I have to get close up the the fitting where the CO2 enters to hear it clearly. This is caused by the CO2 is entering into the tubing ahead of the reactor so I get a high velocity mixture of the CO2 and water at the start which then empties into the low velocity reactor rather than just one large bubble popping out into the water. I really believe this helps the reactor work much more efficiently than just having the CO2 bubble into the reactor too.
I know that feelin' brother! A big pat on the back from me for doing it, they look great!
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