D-D CO2 unit and microbubbles

Discussion in 'Carbon Dioxide (CO2)' started by phillarrow, 8 Apr 2008.

  1. phillarrow

    phillarrow Newly Registered

    Messages:
    24
    Hi everyone, I've recently (and reluctantly) gone a bit more high tech and added a CO2 unit to match my high-ish light output. I bought the D-D unit online and should have received a simple bubble counter/diffuser in one to sit inside the tank (that's what is shown on the website I bought it from and on D-D's site). However, when it came it turned out I had the bonus 'Turbo' unit. Which is basically a small power head that CO2 is fed into from the now external bubble counter/diffuser. I have placed this power head just above, and firing down into, my filter outlet. The power head fires out CO2 micor bubbles and the filter outlet distributes them. The trouble is my CO2 levels are not rising (or rather my pH levels are not falling) and the surface of my tank is completely awash with micro bubbles.
    My questions are:
    Do other diffusers that produce micro bubbles cause this on the surface?
    Has anybody heard of this kind of system?
    Should I change it for a normal diffuser placed under the filter inlet?
    Am I being impatient with the whole thing? (It's only been running properly for two days due to timer problems)

    Also, I have the Tetra Optimat on my nano and this is doing nothing at all. I see no bubbles of any kind and the pH is rising despite me filling the unit three times a day. Anyone got any experience with this? Any advice?
     
  2. Themuleous

    Themuleous Member

    Messages:
    4,126
    Location:
    Aston, Oxfordshire
    i) Yes a diffuser will give you the same bubbles on the surface.
    ii) cant say Ive seen the D&D system in the flesh but they all work on the same principle. I cant see why the pH isn't changing. Have you thought about using the pH drop checker method? What bubble rate are you running at, its probably a simple case of increasing the rate.
    iii) Keep up with what you have for the time being. But a diffuser is a cheap bit of kit should you chose to change.
    iv) CO2 should reach the desired level in a few hours, so you've given it plenty of time.

    v) bin the optimat system, quite honestly its the worst bit of kit anyone ever thought up for co2.

    Sam
     
  3. phillarrow

    phillarrow Newly Registered

    Messages:
    24
    Thanks Sam, I'm running at 2bps at the moment that's why I'm surprised it's not having much of an effect, especially as I'm running on 100% RO (with added minerals to acheive GH of 5-6 and KH of 4-5).
    I wondered why the optimat was so cheap. If an offer looks too good to be true etc.
    Can you (or anyone) reccommend a relatively cheap CO2 unit for a nano tank (25L)?
     
  4. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Hi phillarrow,
    In order to troubleshoot we need a bit more specifics. It's not really clear exactly what specific D&D system you have, what your tank size is, what your filter capacity is and what "high-ish light" means. All of these factors have a bearing on determining whether the system is inadequate or whether your use of it requires adjustment.

    I couldn't find anything on a D&D site but I was able to locate a D&D system here: http://www.aquaessentials.co.uk/index.p ... cts_id=649 Is this the one you have?

    Where have you mounted the powerhead and what is the flow rate of this powerhead? The deeper the powerhead is mounted the better chance you have of dissolving the CO2.

    Where is the filter output? If the filter output is near the surface of the water then this is useless as the CO2 will be already at the surface ith no chance of dissolving properly. Could you post a picture of your configuration?? That would be unbelievably helpful as we might be able to suggest possible reconfigurations to improve system efficiency. :wideyed:

    How are you measuring the CO2 levels? If you are using the tank water to calculate CO2 then you will not have an accurate idea. A dropchecker using 4 dkh water is the standard reference.

    At what point in the day relative to the lights coming on do you turn on the CO2? CO2 injection should begin about an hour or so before lights on.

    Have you reviewed the UKAPS CO2 article (http://www.ukaps.org/drop-checker.htm)?

    Require tank size, filter data and lighting data for further analysis. You should not need to buy more stuff. What you have should work. 8)

    Cheers,
     
  5. Themuleous

    Themuleous Member

    Messages:
    4,126
    Location:
    Aston, Oxfordshire
    The nutrafin yeast kit would be perfect for a 25lt :)

    Sam
     
  6. phillarrow

    phillarrow Newly Registered

    Messages:
    24
    Sam, thanks for the suggestion I'll have a look at that kit.
    ceg, thank you so much for the time you put into your reply. I'll try to put up a picture later on but for now I'll answer your questions:
    That is the right D-D unit you found but as I said it came with a power head.
    My tank is 65cm cube, 220L.
    My lighting is the Arcadia 60cm luminaire with 4 x 24W T5s. I know that the wattage to volume is not great but wattage to surface area is pretty good and I've read a few times that in most cases that's more important (?)
    The filter is an external canister filter which is rated at 1200L/hour
    The filter outlet is a lily pipe and is just over half way down (about 35cm from surface) with the power head just above it and firing down into it. Both are as low as the pipe work will allow.
    I've no idea what the flow rate of the power head is but it's pretty low.
    Both lights and CO2 come on at 11am and are on for 10 hours. I'm checking at about 6pm. I can easily change this for the CO2 to come on earlier.
    I am using the tank water to measure CO2 with a test kit. Yes, I have read the article on drop checkers. The trouble is I'm a reluctant high-tech aquarist and have resisted every new thing I've bought (I've spent an AWFUL lot of money on this in the past few months) and the article scared me a bit. One more thing to buy, one more thing to get my head round. It's now on my next shopping list!
    As I said thanks for your help so far I'll get a pic up as soon as I can.

    Cheers, Phill
     
  7. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Hi Phill,
    I understand completely the fear of the unknown but you're just going to have to get over it if you want to be successful and to justify the amount of money already spent. You cannot be a reluctant high techie. It's all or nothing. High tech or low tech. There is no in between. A 55 USgallon tank is an awfully big tank to be using such a wimpy CO2 system on (sorry if this scares you). In fact this D&D system is probably more appropriate for your nano. A tank this size, properly executed can easily consume 4Kg of Co2 per month. Are you still with me? :wideyed: Here is a regulator I use for very cheap (relatively speaking) http://cgi.ebay.com/CO2-Regulator-Elect ... dZViewItem
    You can then use a Fire Extinguisher or you can use industrial gas supply cylinders from the BOC for example to power the 220l. You can find cheap plastic diffusers as well for this.

    If you insist on using this D&D for the 220L then you will have to crank the valve wide open and mount the diffuser and power head at the very bottom of the tank near the substrate. This will give each bubble more time to rise and to dissolve while on the rise. I'm not surprised at all that you have difficulty saturating the water using this unit. 88 watts T5 on this tank is plenty. Your real problem is how to saturate the tank with CO2 and how to distribute it, especially near the bottom of this very tall tank.

    Your 1200LPH filter is only probably giving you 600LPH so you could actually stand to install another of these filters, but I don't want you to run away in fright. I'm an idealist.

    The JBL drop checker sells on AE for a tenner I think. That's complete with reagent and everything. The 4 dkh water is a little bit more but lasts a while as you only use a couple ml at a time.

    In any case, your path is clear crank the valve open and move the powewrhead/diffuser equipment lower.

    Cheers,
     
  8. phillarrow

    phillarrow Newly Registered

    Messages:
    24
    I'm almost sorry I asked now! But you are right, I've spent this much it's all or nothing now.
    I can't move the current unit any lower as the tubing is already pretty much stretched and if I'm going to buy more tubing I might as well change to a more appropriate unit.
    So, if I buy the one from ebay what else will I need to get? I'm thinking I need tubing, a diffuser and bubble counter, as well as the drop counter. Anything else?

    Cheers, Phill

    P.S. Make your suggestions cheap - my wife is getting suspicious!
     
  9. nry

    nry Member

    Messages:
    1,239
    Location:
    Cumbria, UK
    My suggestion - keep the setup as is but get an eBay glass drop checker for ~£4 delivered. Go to aquaessentials.co.uk and buy the 4dkh water and the linked Hagen pH test kit with bromo blue.

    Put 1.5ml of 4dkh water in the drop checker and a teeny drop of bromo blue. Leave it 3-4 hours and see what colour the liquid is in the drop checker - if it is not green add a little more CO2, if it is yellow add less CO2.

    I would have used the same turbo pump with my D-D set but my tank is too small. Seems an efficient method if you ask me. For my 54litre/15US gallon tank I need 1bps and with the CO2 being on for 10 hours per day I get ~2.5-3 months per 500gram cannister. You can get the same cannister (I am told) from Machine Mart for about £8. You could go for the 2KG fire extinguisher if you wished though, there is an adapter to do this I think from aquaessentials aswell for a few quid.
     
  10. phillarrow

    phillarrow Newly Registered

    Messages:
    24
    I like that suggestion because it's cheap! Trouble is my tank is 4 times the size of yours so to keep CO2 at a decent level would mean changing the bottle every 3 weeks at the most. Besides I want a system for my nano so I'm going to put the D-D one on that and go for the fire extinguisher type on my main tank.
     
  11. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Yes, but Phill's tank is 5 times the volume of yours and it might be 3 or 4 times as deep. There is no way you can compare these two tanks hydrodynamically. Even if you compare from a linear standpoint - 1 bps last you 3 months, 500g would last a 220L 3/5 months or 3 weeks. That assumes 1bps can saturate that tank, which it clearly cannot because he is already using 2 bps and can't get anywhere near required saturation.

    Normally, when you measure pH of the tank water for CO2 calculation you get a false high CO2 value due to the organic acids in the water. Phill's fals high reading is still quite low. This is why I suggested that he move the D&D unit to his 25L nano which would be more appropriate. I'm sorry but I just don't think that system is man enough for a 220L. :(

    For £11 plus delivery you can get a basic CO2 kit which has everything you need to measure CO2: http://www.aquaessentials.co.uk/index.p ... ucts_id=77

    If you were to buy the ebay regulator I listed you would need to get tubing: http://www.aquaessentials.co.uk/index.p ... th=196_252

    The bubble counter is included in that unit already.

    You can find diffusers for every budget on this page:
    http://www.aquaessentials.co.uk/index.p ... th=196_197

    I imagine you would also need filter tubing to make all the connections but that is cheap at your local LFS.

    Finding cheap CO2 cylinders or filling service is the problem here but that is the same problem you would have anyway.

    Cheers,
     
  12. phillarrow

    phillarrow Newly Registered

    Messages:
    24
    Well I bit the bullet and ordered/blagged loads of stuff last night from various places. Thanks again for all your advice. I do appreciate it and hope to be able to do my bit in return for other idiots once I've gained a bit more knowledge.
    Just one more thing. You said the hard part is finding cheap CO2 bottles/refills. Where on earth do I start looking? What sort of places sell large-ish CO2 bottles and/or do refills?
    P.S. I promise that will be the last question for a while!
     
  13. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Hi,
    Breweries, welding supply shops, Pubs, Fire extinguisher supply - they all use CO2. I think NRY mentioned Machine Mart? Ebay sells the extinguishers. Unfortunately I can't help you there because I have to go with the very large sizes due to my tank size of 600L. I'm forced to use the BOC but this is not the cheapest solution. http://www.bocindustrial.co.uk/bocindus ... ioxide.asp

    Perhaps others can chime in regarding suppliers/refills.

    Cheers,
     
  14. beeky

    beeky Member

    Messages:
    879
    Location:
    Chippenham, Wiltshire
    Where abouts are you Phil? I did a quick google search for fire extinguisher supplies in my area and although there were a few red herrings it did come up with a couple of places.
     
  15. phillarrow

    phillarrow Newly Registered

    Messages:
    24
    Sorry beeky, I've not been online for a while, I wasn't being rude by ignoring your question. I live on the Wirral but I've ended up sorting this out myself. After looking around in lots of places I settled on the 3kg bottle from TGM in Wrexham. Although it's slightly more per kg than some ebay stores, the fact that they will refill it for around £20 is very appealing.
    Thanks for all the advice everyone, when all my stuff arrives and I've set it up I'll get a photo up for you all to see how well/badly your advice has worked out.
     

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