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Bob Hoesch


  1. DIY CO2 Injection (LONG)
    by (Bob Hoesch) (Thu, 23 Jun 1994)

DIY CO2 Injection (LONG)

by (Bob Hoesch)
Date: Thu, 23 Jun 1994
Newsgroup: rec.aquaria,sci.aquaria

In article <> narten-at-percival.cs.albany.ed
(Thomas Narten) writes:
~From: (Thomas Narten)

Original article titled "DIY CO2 Injection:  The Yeast Method, Revision 3, 
4/22/94"  not included here.  If you haven't seen this article you should try 
to find it.

Thank you, Tom,  for a very informative and helpful article.  I have just set 
up a semi- DIY system and thought I would share my  experiences also.

Setup:  50 gallon acrylic tank.  Sand (#3 sandblasting grit, 4 bucks for 100 
lbs.) as substrate.  Bottom one inch of substrate has 500 g of Dupla laterite, 
500 g of Hilena Initial D, a handful of washed peat and a few spoonsful of 
autoclaved composted steer manure. Another 2-3 inches of sand on top of that.  
No substrate heating coils or UGF.

Filtration by Eheim 2215, with both intake and outflow divided by a T and 
connected to two PVC tubes with rows of holes drilled in the sides.  I did 
this to 1) maximize water flow-through and 2) minimize strong currents.  This 
seems to work very nicely, as there are few "dead" spots, and tiny particles 
flow across the entire cross-sectional area of the tank.   Filtration was 
initially mechanical with activated carbon.  When plants were introduced the 
carbon was replaced with biological filtration substrate.  Biozyme added at 
this time also.

Lighting:  3-30W Ultra-Trilux and 1-30W CoralLife Actinic (120W total). 
The actinic bulb gives a slightly weird color rendition, so I may replace 
it (unless readers think it is worth having for the plants' benefit)

Heating by 2-75W submersibles, temperature constant at 82F (27.8C)

I  "cured"  (hopefully)  a beautiful, twisted piece of dead manzanita branch 
by soaking it under a waterfall in a mountain stream for about 2 months.  
After I turned on the heaters it grew a little cottony white fungus for a 
while, but that has disappeared.

Tap water here is very soft, low in all minerals and has a pH of around 7 as 
it comes out.  I have to transport all of my water from work, as our home has 
well water with a pH of 9.4 and H2S to boot!

This whole system has been running for about 6 weeks, 4 with plants and 3 with 

5 lb. CO2 tank and regulator from welding supply shop for total of $120.

Reactor made of 1" PVC tubing with 3/16" holes drilled all over it and packed 
with marbles.  The tube is placed next to the pump outflow.  Gas is introduced 
at the bottom and bubbles past the marbles.  This seems to work OK, but 
bubbles sometimes slip out the holes on the sides of the tube. Need to 
tinker with this design a bit.

Initial observations:  I bought a "needle valve" at a hardware store for about 
5 bucks and placed it between the regulator and the reactor.  Turns out it is 
not a needle valve at all--more like an on/off valve--and is inadequate for 
this purpose.  By playing with this and the regulator I can get a flow rate of 
30-60 bubbles per minute coming out of 3/16" tubing.  This was sufficient to 
drop pH from around 7.1 to around 6.6 after several hours.  This appears to be 
stable.  But the flow rate is subject to random variations and I think a real 
needle valve is required.

Plants:  Echinodorus martii, paniculatus, cordifolius and tenellus.  Rotala 
macrandra and indica.  Anubias nana.  Cryptocoryne willisi.  Myriophyllum 
frillii.  All plants from Delaware Aquatic and all arrived in good shape 
except R. macrandra which looked a bit beaten up.  Since starting CO2 about 6 
days ago, growth has increased dramatically in swords, which are now sending 
out new leaves about one a day and growing at least an inch a day.  All 
plants well rooted.  R. indica growing new tips and turning red. 
 E. tenelllus not growing very fast, and I wonder why.    M. frillii is 
still nice and green but not growing very fast.  R.  macrandra is sending out 
new roots but not producing new leaves, and still looks ratty.  Comments 
welcome on this plant.  Green algae is also growing fast, even though I am 
underfeeding the fish.  Water was initially clear, but has been slightly 
cloudy recently.  I'm changing 10-20% of the water several times a week now.

Fish:  so far just catfish.  2-Corydoras julii, 1-C. pastazensis, 
 6-C. pygmaeus, 1-Farlowella acus.   As a side note, I bought the C. pygmaeus 
thinking they were, as advertised, Otocinclus, and didn't realize until 
putting them in their new home what they really were.  My own fault of 
course.  They are very small and actually did look like Otos in the store. 
Interestingly, the store had been selling them for months and apparently no 
one else caught this (or the store is not letting on).  No one around here has 
any real Otos right now and I need to get some good algae lovers.  Suggestions?

Once the CO2 system has truly stabilized I plan on getting 3 or 4 discus as 
the main inhabitants.

This is my first tank since the late 70's (I've moved around a lot...) and 
practically all of my current re-educaltion has been from net.inhabitants.  
I can't thank you all enough.  Hopefully I'll be able to contribute some real 
information as well.

Any comments on this setup would be very welcome.

Best regards,

Bob Hoesch
U.S. Fish and Wildlife Forensics Laboratory
Ashland, OR

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