Sunday, February 26, 2012

Bulkhead through EPDM

Method # 1

I was not sure how well silicone would stick to EPDM until I tried to remove my previous attempt at installing this bulkhead. Rest assured silicone sticks very well to EPDM and Acrylic.

This is a 3/8" piece of acrylic plexiglass fastened with ample amounts of silicone to the EPDM.
Silicone was applied about 1/4" thick on both surfaces and then pressed into place.  I then left about 20 lbs of weight on the glass for 2 days to be sure it had cured.

This is so much cleaner than my first attempt.  Click here to see a job gone wrong.  

The bulkhead tightens down to the acrylic, not the liner.  A hole larger than the nut was cut in the liner and the plywood so that the bulkhead would seal directly to the acrylic.  The silicon makes the seal between the EPDM and the acrylic.   I used nearly half of a large tube of fish safe silicone.  This is no place to be skimpy.  You can see in this photo how much squeezed out.  After two days this connection was cured and extremely strong.

One thing to consider is the size of the glass should allow your bell to sit firmly on the glass.  If you cut the glass too small the bell will have a tendency to tip.

When you tighten the bulkhead go hand tight and then a 1/4 turn with a wrench.  Do not over tighten as this will squeeze the soft washer out of round and you will have a leak.

Method # 2

For the fish tank overflow I used a different method.  It worked equally well and provides a more stable fit.
In the example above the bulkhead will move with the liner.  For the overflow I wanted a study connection had would not flex.

This method requires a little more care as the hole in the liner must be cut round and just slightly smaller than the bulkhead.  It's not as easy as it sounds.

The seal is made directly to the liner with this method and there is no silicone used.  The acrylic provides a smooth surface for the bulkhead to tighten down on.   In this picture you are looking at the back side through the glass.  A small section of the tank wall was cut out and this piece of acrylic was installed with screws to make it a solid inset.  The acrylic is part of the tank wall and this photo is looking into the cavity of the wall from the outside.  You can see the bulkhead nut tightened against the glass.  The soft gasket is on the inside of the tank between the bulkhead and the liner.  The liner is pressed against the glass, but the seal is made at the soft gasket and the liner inside the tank.  An added benefit here is that I will be able to see any leaks if they occur .  But this is a very secure bulkhead installation and should be free of any problems for a long time.

Thursday, February 23, 2012

Connecting a bulkhead to an EPDM liner

I want this to be done! But this bulkhead is giving me a lot of grief. I get that it was not designed to connect to EPDM, so here's the solution I have come up with.

 I cut a piece of 3/8" plexiglass and applied a lot of silicone to the underside. Then I washed it, and the EPDM with denatured alcohol and applied this fish safe EPDM seam tape.

One thing I've learned is that if the bulkhead is over tightened it will squeeze the soft inside gasket out of round, and cause the seal to fail.  I'm not sure... this might be what happened yesterday, but if this does not work I'm just going to smother the fitting with even more silicon until it complies.

This has turned out to be a lot more difficult than I ever imagined and I'm tired of dealing with it!


I found the source of my leak.  In my attempt to squeeze all the bubbles out of the silicone I literally stood on the acrylic and jumped up and down on it.  Apparently I caused a small crack in the plexiglass, and the leak.  
To view my repair which was done with much more silicon and care click here.

I'm taking no chances.  This hole saw fit over the bulkhead and the two lead weights and a 3 lb hammer will keep the pressure on over night.

I might be overly optimistic, but I have faith, and have begun to shovel gravel into the grow bed.

Testing the Bell Siphon

In this picture you see the 800 gallon fish tank on the left.  The grow bed on the right and the sump tank below.  These tanks are built with 2x4 walls filled with fiberglass insulation.  The bottom and walls are also lined with sheets of 1-1/2" rigid insulation..  I added this more for puncture protection, but the extra insulation should also help keep the system at a constant temperature.

Here I'm  testing the bell siphon and it's water tight connection. At first the length of the drain pipe needed to be adjusted so that the siphon would break, but it's working now.  I used a 1" bulkhead and 1" standpipe with a 2" bell.  The bell has 3 - 3/8" legs cut at the bottom.

Sealing the bulkhead to the EPDM has been a challenge. I'm a little anxious about that, so just to be safe I have decided to drain the grow bed, and cover the connection with silicon before adding the gravel today. I finally had to cut a larger hole in the plywood and set a 3/8" x 6" x 6" piece of plexiglass over the hole.
I decided to use 45 mil EPDM in the grow bed because of my concern for the sharp edges of crushed gravel, but the problem I keep encountering is the 45 mill Firestone EPDM is so soft, and stretchy that it can easily be pulled out of the seal.

I used 10 mil Pond Skin in the other tanks.  This was purchased at Home Depot and is not Firestone.  This 10 mil Pond Skin does not have the same soft and stretchy character.  I have yet to install the overflow from the fish tank, but my preliminary tests lead me to believe I will not encounter these problems with the 10 mil.

If I continue to have problems with the 45 mil EPDM I will glue a patch of 10 mil to the 45 mil or if the test I'm performing now proves workable, I may silicon the plexiglass to the EPDM and make my bulkhead seal directly to the plexiglass.

Monday, February 20, 2012

Nitrite levels

February 13

I installed the wet/dry sump

February 20

 My nitrite levels continue to run high, but the ammonia has gone to zero.  Waiting for the second tier of bacteria is like waiting for your bangs to grow.

  UPDATE February 26 

I built the wet/dry sump on the 13th.  Nearly two weeks later I have begun to see  Nitrobacter and Nitrospira begin to bloom!

To keep my fish healthy I have done 75% or better water changes everyday.   What a relief this is.   I chose to add fish before cycling only because of the rare opportunity to get these fish locally.   I would never recommend placing fish before the tank is cycled.

Nitrite oxidoreductase

From Wikipedia, the free encyclopedia
Nitrite oxidoreductase (NOR or NXR) is an enzyme involved in nitrification. It is the last step in the process of aerobic ammonia oxidation, which is carried out by two groups of nitrifying bacteria: ammonia oxidizers such as Nitrosospira, Nitrosomonas and Nitrosococcus convert ammonia to nitrite, while nitrite oxidizers such as Nitrobacter and Nitrospira oxidize nitrite to nitrate.
The enzyme is bound to the inner cytoplasmic surface of the bacterial membrane and contains multiple subunits, iron-sulfur centers and a molybdenum cofactor.[1][2] The enzyme is relatively abundant, making up 10-30% of the total protein in these bacteria and forms densely-packed structures on the membrane surface.[3]

CLICK HERE for details of my aquaponic system cycle

Tuesday, February 14, 2012

Building an 800 Gallon Tank

I learned that deck screws are not strong enough to hold the bottom plate. I ended up using 5/16 galvanized lag bolts.
Folding the liner is a lot harder than it looks. Here's a link that may help
Building an 800 Gallon Tank

Rigid Insulation was laid down first

Lessons learned.  This tank lasted about 2 years.  First mistake was not wrapping the liner down over the outside.  Spilled water got between the liner and the wood.  The sides rotted out.
There were many times I forgot to turn the water off while filling the tank.  I flooded my shop several times and the moisture under the tank rotted the tank.   If you build a wood tank take every precaution to keep the wood dry.

Saturday, February 11, 2012

Systems Update

I'm building an 800 gallon tank (128" long by 36" wide and 50" deep) with a 250 gallon wet dry sump tank and 30 sq ft grow bed.  I'll have about 1000 gallons of water in this 900 cu ft room!  Basically 15% of the room will be filled with water.  The proportions may not seem correct, but I do not intend to raise the fish in a maximum population configuration.  Happy fish and stable temps are my goal.

I was going to use IBC's, but I want to maximize the space I have in the grow room I'm building, and now plan to custom build the tanks with EPDM.

Life is getting a little busy, but I hope to have the tank done. and filled next week.  I can hardly wait!   I've learned my lesson about cycling and want to get the process started.

I set up a 30 gallon tank last week and thought could barrow some bacteria from my pond. Well here's a little insight on that.  It appears that during the Winter the bacteria go very dormant or die.  I added fish, but the filter was not ready.  Let me tell you it's no picnic having to do 25% water changes at least once a day to maintain a <1% ammonia level.

I added Aqua Gold yesterday and today I added Nite Out ii.  Within two hours of adding the Nite Out ii the ammonia began to drop!  Good stuff, but my friend Fred may still be right about the Aqua Gold.  Between the two of them it looks like I can relax.

I started to build a wet/dry sump tonight.   The little filter I have on the 30 gallon tank is not going to be able to handle the  population much longer.  Below is the design.  

 I don't want to take a chance on a siphon over the side to the sump tank. .It will be my first time drilling a hole in glass,but I have two 30 gallon tanks and I'm feeling confident that it will go well. 

The 3 grades of Matala Filter Media is placed as shown above the water level and under the drip pan.  The larger section is the refugium and water level section.   It may seem wrong, but this is the direction Matala Filter Media is supposed to be used

Sunday, February 5, 2012

Evaporative Cooler Design

Yesterday I installed a whole house fan in the grow room. I could purchase an evaporation cooler but I've never been trilled with the designs. This is my design similar but better IMHO than a MasterCool. I will duct the air from this cooler into the room and let the whole house fan pull the cool air in.
Click Here for my SketchUp Files

This is the water section of an evaporation cooler. It contains three sub-sections, the Drip (Gray), Filter(Blue), and Reservoir (Yellow). A squirrel cage fan connected to the back face draws air through the filter section. The drip section contains 1/2" PVC drip tubes. This top section is removable in order to replace the paper pads The paper pads are supported front, back and bottom with 1/2" PVC in the filter section The filter section is made of fiberglass. A pump and float sit in a fiberglass reservoir section providing easy access. The filter section can be stacked with only one drip section (Gray) at the top and only one reservoir section at the bottom. This will create an even larger cooling unit I was not able to extrude the drip pipes or connect the pump as I would like.