Putting in air in my rafts need help

[Joe Bifano]

I am putting in soak-er hose in the bottom of my rafts. As I am putting this in I am having trouble keeping them on the bottom becasue they float up. I tried sand in plastic snack bags and will try quart bags next.

I was wondering if I could use lead weights with fishing line to hold the hose down but I am affraid of the lead leaching into my water.  Does anybody know if lead will leach?

Is there any ideas you all might have to keep the hose down?

[Todd Sowell]

Why not use airstones?

[Joe Bifano]

I may have too but a 50' soak-er hose is $10. and each 12" air stone is $10. How many air stones would you need for a raft 24' long 4' wide?

[Todd Sowell]

You would need one stone every 4 feet

[Joe Bifano]

Is that a 4" or 10" or 12" stone? In my setup that would be 28 stones @ over $6 to $7 comes to $200. I spent $50 on the hoses so I am hoping to use these first.

Todd Sowell said:

You would need one stone every 4 feet

[Todd Sowell]

The information I am using is from Dr Rakocy formerly of UVI. He uses 6" airstones

[Vlad Jovanovic]

You wouldn't happen to know the cfm rating for those stones would you Todd? I've got a bunch of different air stones, some of which are the same length/size, but put out different amounts of air nonetheless...I'm trying to figure out whether to go with:

1) The soaker hose idea (Chris Smith at Coastview Aquaponics used one, which is where i first got the idea from last year. I remember that he was diggin it, but I think he no longer uses it for some reason if I remember correctly). I have no idea how I'd go about sizing a blower for this option...Probably just ask Chris I guess?

2) Use two lengths of 1/2" PVC attached to one another along the length of the trough. One pipe would be filled with sand, capped off, and would just serve as a weight...while the other would be drilled with 0.6mm holes wherever I "saw fit". Again, sizing a blower is guesstimating at best...

3) Use the same AS8L medium pore air stones rated at 0.35cfm that i got for the fish tank. Using one air stone every four feet along the trough, ala Friendly's etc... With a known cfm rating at a given depth, sizing a proper blower should not be difficult...neither would figuring/knowing about out how much air is being put into the troughs...Of course this is the most expensive of the 3 options...Would like to know exactly what UVI uses, though my water temps will rarely get as high as theirs do...still though... 

[Todd Sowell]

Sorry, no. He does mention adjusting the flow to get medium sized bubbles for better agitation.

[Vlad Jovanovic]

Dratz...

[David Hart]

I cut short sections of rebar and used tye wraps to hold them to the soaker hose. The hose does get dirty and can be a pain to clean it

 

 

 

 

[Joe Bifano]

Hey David. Does the re-bar do anything to the water as far as leaching steel?  Is that okay? I have a ton of re-bar.

[TCLynx]

I would chose re-bar over lead.  Definitely don't want to add lead to your food supply.

[Ryan Chatterson]

Todd- Dr Rakocy actually used 3" stones (0.35cfm) every 4', not 6" stones. He either uses 6" or 12" in the fish tanks (can't remember off the top of my head)

You can use gravel bags, rebar, a separate weighted pipe or run them through cured concrete blocks. The main problem is that when you use a soaker hose you dont have very uniform bubbles and in most cases a small strip of soaker hose will allow more air to pass then a stone meaning you need a larger air source to power the same number of drops. I realize you don't want to spend more money when you already have this stuff but it's really just not the right tool for the job (IMO). Plus they wear out pretty quick (it stretches to let out air but looses its elasticity so the bubbles get larger and larger over time.