# CO2 APS EF2 reactor with internal Venturi fitted - testing ATM



## Zeus. (17 Apr 2018)

HI all

been thinking about how to improve my APS EF2 CO2 reactor

Venturi and Cones come to mind OFC so came up with 'rough' drawing of an internal venturi that will suck the gas (CO2) at the top of the reactor back into the main flow, plus and inverted cone to make more turbulence






So it works a bit like an inductor, The cone could be made with a plastic funnel and the venturi could be made from scratch or one of the many 'Venturi Fertilizer Mixer Injectors' on ebay.

Your thoughts guys

Zeus


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## ian_m (17 Apr 2018)

Keep up at the back there.....already done by Edvet, picture in link.
https://www.ukaps.org/forum/threads...th-drip-water-change.52693/page-2#post-519869


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## foxfish (17 Apr 2018)

Good idea but I would increase the cone sides to near the bottom & exit the water back out the top.
Which is what I did by using a plastic bottle inside a water treatment vessel.
However I found that during my experiments, there was a fair bit of fine tuning required ... it was not an easy project but fantastic (if expensive) fun.
I used plastic bottles but found that the shape and length of the bottle produced wildly varying results!
Certainly the key for my projects was a clear vessel.
 I tried out a venturi but in the end discovered the perfect bottle & the Venturi  was not required.
The cone shape certainly recirculates & aggravates the bubbles but I still got a certain amount of trapped gas, however I found that the build up was limited to around 25mm & that dissipated really quickly once the gas was tuned off.

Without doubt the best reactor I built used a vortex to spin the water & it worked flawlessly with zero build up but I was always nervous of the construction as it is really difficult to DIY an entry pipe at a tangent.
I think I could build one now that I have a better workshop & tools but as I don't actually have a C02 injected tank at the moment, that would be a bit pointless!

I have plans to build a back flushable filter similar to a Koi pond bead filter, I am sure it would also serve to dissolve huge amounts of C02 as well as filter the water.... just need to find the time....


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## Zeus. (17 Apr 2018)

ian_m said:


> Keep up at the back there.....already done by Edvet, picture in link.
> https://www.ukaps.org/forum/threads...th-drip-water-change.52693/page-2#post-519869



Thats the PIC/thread that gave me the idea of moding my present reactor  the only real difference is mine would be more compact and all within the APS EF2 chamber



foxfish said:


> Certainly the key for my projects was a clear vessel.



Yes thats an Issue with the APS EF2 as its not clear- been on to APS to see if they can do a clear chamber like in one of the pics they use to advertise the filter, only need one for R&D but the answer was white only 




foxfish said:


> Good idea but I would increase the cone sides to near the bottom



Thought that also but just rough pic, all would be dependant on what I could use cheaply eg funnels of cones already made and for sale cheap



foxfish said:


> exit the water back out the top



Why as the CO2 bubbles that get past the rim of the funnel/cone would rise and then exit to the tank  instead of getting sucked back in to the inlet flow of the venturi 



foxfish said:


> Without doubt the best reactor I built used a vortex to spin the water & it worked flawlessly



Been thinking about that too, maybe a cheap pump taking water from the lower chamber and back in at the top to create a vortec/spin but it would mean modding the chamber walls and getting the right fittings.

Plus is having the time to sort it all out  its all Alpha ATM

Thanks for the input  easier to do with input for like minded folk who have a good insight /experience


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## foxfish (17 Apr 2018)

If the cone or bottle or whatever goes right down to within 25mm of the bottom, then the water will then travel back up the outside and double the travel distance & contact time. If you could design another inner tube then the contact time would be trebled.


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## AverageWhiteBloke (17 Apr 2018)

Just regarding the clear canister, the eheim classic is opaque and you could maybe remove the impeller and just use it as a pass through or maybe you could cockle something up using the water purifiers that are available like in the pic.



Sent from my STH100-2 using Tapatalk


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## foxfish (17 Apr 2018)

Two other designs I have built .... reverse bottle and vortex ...


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## foxfish (17 Apr 2018)

This one worked very well ......


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## foxfish (17 Apr 2018)

I took it one step further with this spinning device ....


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## Zeus. (17 Apr 2018)

Thanks Foxfish nice work and thanks for sharing food for thought definaty.



AverageWhiteBloke said:


> Just regarding the clear canister, the eheim classic is opaque and you could maybe remove the impeller and just use it as a pass through or maybe you could cockle something up using the water purifiers that are available like in the pic.
> 
> 
> 
> Sent from my STH100-2 using Tapatalk



Bought one of those filter purifiers but thought it would never be up to the job on my tank plus the reviews I had seen on you tube they was always so noisy.

One thing I like about the APS EF2 is it's pretty wide so flow is slow internally, plus mine are pretty quiet IMO but they do collect a large bubble with my BPS rate.


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## Zeus. (28 Oct 2018)

Have been sat on this project far too long, the biggest issue was making the APS EF2 have some window I could see whats going on inside, lots of ideas on how to do it even had a spare APS EF2 ready to mod and use just for testing, however can never find the time to do it. I did however have the  internal venturi sorted for months was waiting to make the window in the APS EF2.

So decided to go ahead without the window and see what happens to the pH Profile.

The internal self feeding ventri for the APS EF2 is simple





Bit of 15mm plastic mains water pipe with the metal ferrule in the end with a 1.5mm hole in it. the 1.5mm hole is at the highest point in the reactor chamber so should work well with the CO2 being pressured in the main flow of the water.
The bore diameter pre ventri is 12mm and the ferrule has in internal of 9mm. Does it work Yes tested it with a bit of saliva in the 1.5mm hole and just blow though it, the saliva was sucked in the hole np.
Just by chance the plastic pipe fits really snug in the lid of the APS EF2, so no need to glue



Lady luck was on my side 
I did have some plans to get the water swirling round and funnels in the reactor, but decided on the KISS principle first and see how it goes.
Decided on a short pipe to start off with and see how it goes with a few side holes as well. Also decided the leave the lower black plastic sponge resting plate in as felt it might help stop the bubble jet from reaching the bottom, however might not be needed as the APF EF2 does have quite a large diameter of 120mm, this same large diameter will increase the Pressure of the water in the reactor, as the slower the water flow the higher the pressure as per *Bernoulli's principle* which is what I believe is the advantage of the APS EF2 over many off the shelf CO2 reactors as well as its price, its not just the length that helps its the width ( calm down boys ) as the wider the reactor chamber is the slower the water the higher the pressure and the higher the pressure the faster the uptake of CO2 by the water, plus more time for the CO2 bubbles to rise. This incresed pressure in the reactors chamber is why I believe I am able to get such quick pH drops along side duel CO2 reactors/injectors and insane BPS OFC
Took all the bio balls out of reactors as I dont think they will be needed.
pH pen calibrated and ready to start CO2 very soon


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## Zeus. (28 Oct 2018)

pH Profile so far




Which was a little of a surprise as it took 43mins for pH drop after WC with glass covers off  yesterday and 53 mins the day before with glass cover on. The flow restriction on the bypass was a little lower than I have it normally so less flow through reactors than normal but not much.
The pH drop is always faster after a WC IME and always slower with the glass covers off also, so its taking about the same relative time IMO may be faster with the BioBalls in the reactors also OFC, but no fizz in tank and will see how the rest of the pH profile goes for rest of day, although I do expect it to drop very slowly till I get the glass covers back on, but after removing some Tenulus Brown from my carpet if time allows so after easy access


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## Zeus. (28 Oct 2018)

Full Profile for the day




Not too shabby. Will have to see how long the pH drop takes tomorrow which is pretty easy as PLC records it.




Kessils ramping down from 80% intensity and spectrum ATM. Not sure if the venturi is working well could do with that window in the spare APS canister to observe the bubbles OFC. A longer bit of plastic pipe might be all thats needed Plus do have another design which should create a swirling vertex as 'Foxy' suggested seemed to work well. Increased the pre on time for the CO2 Via PLC to 65mins 

edit- forgot to add DC colour


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## Zeus. (2 Nov 2018)

So after nearly a week the speed of the pH drop was on par with what it was before. So I made some viewing windows for testing







Nothing fancy just enough to test and see whats happening, I didnt trim the plastic measuring cups as they was a little brittle and one cracked when I did, but seeing as theirs no vortex in the reactor it would make little to no differerance IMO. I was a little concerned if they would hold 





But they did so far anyway. The venturi does work when the gas goes off but it wasnt massive you can see a little bubble in the lower window, in the upper window you can just make out the surface of the water but was hard to get a decent pic. If I increased the flow though the reactors the venturi worked better with more bubbles, but it started to have a few bubbles make it to the bottom and came out of the spraybar.

So I creased the length of the plastic tube so it just reached the bottom of the reactor





To deflect the bubbles away from the output fitted a little deflector to the bottom of the reactor 


pic little out of focus but the deflector was just a plastic tube trimmed to height and bit of silicone to hold in place,  the 15mm pipe went into deflector a bit. stopped bubbles hitting bottom of reactor then being pushed toward the outlet pipe

This worked better with a slightly faster pH drop with similar flow as before and the pH has held steady at the same BPS, they do work better with higher flow but they do make some noise compared to what the reactors with the Bioballs fitted and no venturi, but a large bubble does get in the reactors

So not that good IMO would rather have them quiet and use more CO2

pH profile (only noted pH till shortly before CO2 off, I was having a quick check every 30mins or so and it was holding pretty stable)






In pic below you can see the large CO2 bubble at top of reactor and the bubbles rising in the water I had the CO2 injection off at the time




Plus 1 hour after CO2 being off the large CO2 bubble at the top of the reactor was still there, smaller but there all the same. No way near as fast as 'Foxys' swirling vortex at clearing the CO2 bubble ( his took about 15mins)

Next up the inverted funnel








Which does fit in the reactor quite nice, the hole in the funnel is to allow the gas to get back to the top of the reactor and  venturi intake. Issue with this is it does shorten the height of the reactor but........... Only just silicone it up so will fit tomorrow and test
Might work well with a layer of bioballs between the sponge plates of the reactor!
ie



As you can tell I have spared no expense on this project


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## Zeus. (3 Nov 2018)

Got the inverted cone/funnel fitted and left some air in the top of the reactor for seeing how it worked and so far with visual inspection I was impressive and not too noisy either as if I let the air go into the other reactor is was noisier than the inverted cone. The venturi draws the air in so lots of bubbles in the lower window




the higher the flow the more bubbles OFC but even on its lowest flow there was a steady flow of bubbles and pretty quiet too.

In the upper window can see the water level in the inverted funnel and the bubbles coming out of the 6mm hole in the side of the funnel




Obvious its just atmospheric air ATM and the real test will be with the CO2 and pH profile, plus only had one funnel that would do the trick,I have fitted it to the trickle CO2 line ATM so if it does increase CO2 uptake the pH profile wont be steady today it should keep decreasing pH and will have to decrease BPS or in my case working PSI

Bioballs and sponge plates wont fit the the testing reactor with the windows


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## Edvet (3 Nov 2018)

Impressive testing!!


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## Zeus. (3 Nov 2018)

Edvet said:


> Impressive testing!!



Cheers m8  I would just like to try and improve my system and sharing how it goes .

Well thought this was going to better as not as noisy IMO so it is the best so far out of the Test but during the test pH valves was more or less the same and pH holding steady for so increased the flow though the reactors and noise OFC but no change in pH  that surprised me. The reactor was filling up with a large CO2 bubble at the top too, you can see the level on the upper window



So extended my light period for the rest of test. and fitted the reactor with bioballs and internal venturi pipe




ran it for 45mins and no decrease in pH but quieter. So was running out of CO2 period so extended photo period ( which thanks to Ians brill software auto adjusts the CO2 period on PLC) and fitted the inverted funnel and Bioballs




only the lower sponge plate was fitted and the bioballs was going up into the funnel too. This was the quietest so far IMO or was that the emperors new clothes kicking in . Not really enough time to see if it effect the pH

pH profile for day



speed of pH drop about the same, but only one funnel fitted - ordered some more funnels 
But the speed of the drop of about 1.0pH was about 15mins  




Run again tomorrow

Some things may need some change like a smaller hole for the venturi as 1.5mm is quite big. Also with me having a 500l tank and such a big pH drop and High [CO2] there are limits to what can be achieved and the higher the [CO2] we will see diminishing returns for any increase in CO2 injection rate to to loss of CO2 from the surface OFC. I do think the inverted funnel with the venturi pipe is the way and if it wasnt for such a big pH drop and corresponding Massive BPS I dont think it would get the large bubble. If nothing else I have a stable pH once lights on  
The other thing I could do is have the injected CO2 from both injectors feeding both reactors then that will double the surface area of CO2 in contact with the water for the whole CO2 injection period and not just the pH drop period  just need a few fittings and to do it OFC


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## goldscapes (5 Nov 2018)

Have you thought about creating a vortex by directing the flow round the inside of the canister using some filter hose? You could attach it to the end of the short Venturi nozzle then twist it round in a spiral so the water exits the tube at the edge of the canister.
It might get in the way of itself but just a thought.  Loving the enthusiasm and determination to make this work! Go Zeus!


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## ian_m (5 Nov 2018)

Going to reveal my hand here, as I have not got round to building "my idea" but Zeus's activity on CO2 dissolution reminded me. This is what the extra relay output "CO2 Pump" was for on my PLC controller, in 2016 but not ever got round to it .

Basically CO2 doesn't dissolve very fast in water, so what all these reactors, injectors etc all try and do is prolong the contact time between CO2 bubbles and the water.

So you get a length of pipe and pass the water and injected CO2 along it, allowing time for the CO2 to dissolve. You will probably need to put smaller diameter tubing in the big tubing, to stop the CO2 forming a big bubble.

So picture below shows a pump pumping water via a CO2 injector, then into a coil of tubing, say 2-3 meters, filled with smaller diameter tubes.




Use this calculator to see how many smaller pipes you can get in a bigger pipe. In my picture I have 7 off 5mm pipes (outside diameter) inserted in a 16mm (inside diameter) pipe.
https://www.engineeringtoolbox.com/smaller-circles-in-larger-circle-d_1849.html
This reduces the cross sectional area from 200mm2 (16mm) to 113mm2, which is nearly the same as 12mm2 tube, so you could get away with a 12mm2 pump. A valve to regulate flow before going into the tank might be helpful to slow the flow as well.

So Zeus, throw your reactors in the bin and use PVC tubing. 

Oh, not tested this idea, but I bet Zeus is up to the task.


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## Andrew Butler (5 Nov 2018)

Well if we're revealing our ideas the here's my hand....
Either a spiral cone nozzle (first pic) which would create a vortex within the chamber or an eductor (2nd pic) which works using a venturi effect.
Nothing new; just parts that could ease what you're trying to achieve.


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## Edvet (5 Nov 2018)

Originally my sump-output went into a much wider pipe ( 32 mm to 10 cm pipe) which was fully summersed in the tank. It had some plastic bio balls in it and i just put the CO2 hose about 1/5 of the length from below in it. Thew full flow through that was something like 1000 lit/hour, worked good
You can see it on the left side of the tank



38068787_00005295 by Ed Prust, on Flickr


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## Zeus. (5 Nov 2018)

Sundays results very simualr to Saturdays



davexcape said:


> Have you thought about creating a vortex by directing the flow round the inside of the canister using some filter hose? You could attach it to the end of the short Venturi nozzle then twist it round in a spiral so the water exits the tube at the edge of the canister.
> It might get in the way of itself but just a thought.  Loving the enthusiasm and determination to make this work! Go Zeus!



Yes have had a few ideas on making a vortex but trying to keep it simple at the moment more pipes mean more potential cleaning and cost also. 



ian_m said:


> Going to reveal my hand here, as I have not got round to building "my idea" but Zeus's activity on CO2 dissolution reminded me. This is what the extra relay output "CO2 Pump" was for on my PLC controller, in 2016 but not ever got round to it .
> 
> Basically CO2 doesn't dissolve very fast in water, so what all these reactors, injectors etc all try and do is prolong the contact time between CO2 bubbles and the water.
> 
> ...



Will have to have a think on this one M8 



Andrew Butler said:


> Well if we're revealing our ideas the here's my hand....
> Either a spiral cone nozzle (first pic) which would create a vortex within the chamber or an eductor (2nd pic) which works using a venturi effect.
> Nothing new; just parts that could ease what you're trying to achieve.
> 
> View attachment 119260 View attachment 119259



Either of them may work well, may need high flow for them to work also!. Will have to try them when my present ideas run dry M8

________________________________________________________________________________

So my present venturi and funnel is working and cost about £5 tops just needs some tuning IMO and it is quiet which in my book is a big plus. The present tests show us that the system is working about the same as no venturi fitted, however it has provided a baseline to work from, plus the venturi does work visually in the windows

The Venturi pipes main flow diameter is about 9mm and a smaller diameter will create a bigger pressure drop and more will be drawn back into the main flow so the new one is 6.5mm, yes we need flow but if I have my bypass fully open the reactors work just as good as partial closed or fully closed just less output from the spraybar, plus the reactors get nosier with increase flow. Will the reduced flow impact the time it takes to get the pH drop ! I dont think so as at present I get a 1.0pH drop in 15mins going off my pH meters. If it works at my present BPS/PSI I think it will be even faster once the venturi works better  Testing will tell OFC







Bit of resin glue to retain the smaller pipe in the metal ferule and more resin for the ferrule in the pipe.

Next is the small hole in the venturi which draws the CO2 back into the main flow 1.5mm was the smallest drill bit I had so ordered HSS Twist Drill Bit Set Tiny Very Small Micro Model Craft Drill Bits , 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0, 1.2, 1.3, 1.4, 1.5, 1.6mm. Smaller hole means smaller bubbles combined with a bigger pressure difference should get more smaller CO2 bubbles back into the main flow. I can start off small and work up and with the window in the reactor I can see the effect straight away. The big bubble in the CO2 reactor is telling us that its not being sucked back into the main flow fast enough there should be more smaller bubbles in the main flow which we should see in the window and no Big bubble should be building up at the top of the reactor.

If I can get this to work right could always get son to get some 3D printing done at Uni for a more professional job, instead of just using bits and pieces I have in my garage


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## Andrew Butler (5 Nov 2018)

Zeus. said:


> 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95


Have you got a drill with a chuck that accepts these sizes?!


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## Zeus. (5 Nov 2018)

Andrew Butler said:


> Have you got a drill with a chuck that accepts these sizes?!



4 HSS Pin Vice Set


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## Zeus. (11 Nov 2018)

Andrew sent me his eductors which he had had no success with one was too big and so was the spiral mixing nozzle but one had a hope




so drilled out my 15mm plastic pipe with an 1/2inch drill and it fit real snug and the pipe fitted the lid of the APS EF2 nice






when I tested with the APS EF2 with the windows it worked but not quite as many bubbles as the new venturi I had already done and had a little test with, plus it didnt draw the air back as high in the APS EF2 as my DIY venturi. But thanks all the same Andy  well worth the try M8





Bit of epoxy resin bit of time pre drilled the metal ferrule as did think the fine drilled could handle it. Started off with a hole 0.5mm but that was a little noisy so increased it and at 0.9mm the bubble rate was good and noise was low so went with that. Only had one funnel to use as the others hadn't turned up.









Faster pH drop but had just done WC so would expect that due to CO2 in the new water. Still got a bubble building up in the reactor not quite as big but not much different.
repeated today OFC

Just done the pH drop



so same as before no net gain.

Yet there was more bubbles being generated with the new venturi. The smaller internal diameter of the venturi had *NO *net effect on the speed of the pH drop. The tank pH once lights on and booster period over did seem a little more stable yesterday .
Also noted that if I fully closed the Bypass there was even more bubbles but dont want to reduce the tank turnover ATM plus extra load on the filter pump too.

I think if the CO2 uptake was increased than we should have no bubble in the top of CO2 reactor. More tweaks to do/test. Plus I should also fit the reactors as before and check how they perform again plus see how they work with the window   never did check that


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## Andrew Butler (11 Nov 2018)

Zeus. said:


> well worth the try M8


I thought the spiral one would have fitted and been the most likely to work. 
I think the eductors depend on a high flow rate to make them work properly but nothing ventured, nothing gained.


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## Wookii (10 Feb 2020)

Where did you get to in the end with this project Zeus? Where did your final design finish up?

Incidentally, I noticed that you can get these pre-filters with clear bodies now in a few different sizes:

https://www.ebay.co.uk/itm/Aquarium...-Accessory-Pump/223748002571?var=522465291893

I assume they're all made by the same OEM manufacturer that makes them for All Pond Solutions and Sun Sun etc, so the clear body might be a straight swap for the EF2 body (?) and allow you to see easier whats going on with the bubble movement.


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## Nigel95 (5 Dec 2020)

Wookii said:


> Where did you get to in the end with this project Zeus? Where did your final design finish up?
> 
> Incidentally, I noticed that you can get these pre-filters with clear bodies now in a few different sizes:
> 
> ...


Hey this link is dead do you have any other links or names for the product?


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## Wookii (5 Dec 2020)

Nigel95 said:


> Hey this link is dead do you have any other links or names for the product?



If you put “LW-603” in eBay search you get a few resellers:









						Transparent Aquarium Canister Filter Efficiency Portable Fish Tank Bucket  | eBay
					

Find many great new & used options and get the best deals for Transparent Aquarium Canister Filter Efficiency Portable Fish Tank Bucket at the best online prices at eBay! Free delivery for many products!



					www.ebay.co.uk
				




There are three sizes available.


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## Nigel95 (5 Dec 2020)

Wookii said:


> If you put “LW-603” in eBay search you get a few resellers:
> 
> 
> 
> ...


Just found them a minute ago haha. Thanks anyways!

I was wondering if those EW 604 are a good fit for 16/22 filters. As in real 16mm diameter so it doens't cut the flow extremely hard by making making the diameter more narrow than the 16/22 hoses of the filter.


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## Zeus. (5 Dec 2020)

Wookii said:


> Where did you get to in the end with this project Zeus? Where did your final design finish up?
> 
> Incidentally, I noticed that you can get these pre-filters with clear bodies now in a few different sizes:
> 
> ...


Opps missed that post, sorry M8.

No further testing has been done and I just accepted them as they was.



Nigel95 said:


> I was wondering if those EW 604 are a good fit for 16/22 filters. As in real 16mm diameter so it doens't cut the flow extremely hard by making making the diameter more narrow than the 16/22 hoses of the filter.



Well the APS EF2 and all its descendants as far as I am aware are all the same and just rebranded with different names and numbers. If my memory serves me correct the true 'bottleneck' is the fittings themselves which doesn't change regardless of what size hoes you fit, the two fittings for the hoses have a smallest diameter of 12mm, which when going from 16mm to 12mm does sound much it does make a big difference - I don't have the maths handy


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