Backyard Aquaponics
A place to discuss aquaponics

where's the sodium coming from for this? or is this just in seawater?

Steve,
Isn't the 'saturation' point the normal capacity of the water to hold DO? So a body of water at sea level has a higher capacity for DO. As well then a warmer body of water has a lower capacity. So a brackish body of water at a high altitude that is above 80*F will then have a low capacity for DO. Right?
I mean ppm or mg/l work out to the same and are a real measure of the level of DO in water. Less DO is still less DO regardless of the factors, isn't it?

In my case, I want to maximize my crayfish density as much as possible, but being at 4100 feet I know that my waters capacity is reduced as well because the redclaws prefer water in the mid 80's temperature range, the waters capacity for DO is further reduced. So at 80*F, the DO saturation point is about 8ppm and then factoring in the altitude the waters saturation point will be 6.88pmm. That's without any other factors or organisms stealing DO from the water and my crayfish. Or am I missing something?

I just really want to understand this. As DO is life for aquatic animals.

am assuming the sodium is coming from sodium chloride (NaCl or salt)

im not sure (im thinking not), this is just some food for thought BUT:
Isn't caustic soda (NaOH) corrosive, and wouldnt that equation leave free clorine ions to form chlorine gas which would kill things either in solution or when it gasses off in an enclosed space (eg aquaculture facility)

i am guessing the lower DO saturation point in salt water is due to its density (already has a bunch of stuff disolved in it, salt, potassium, etc.... and hence less room for 02 molecules). But this is just a guess....

I have no hard data on this, it was a random thought given a few variables that seem to coincide with seawater having high pH and lower general DO than freshwater.

rassd, you got it ALL right.

We may be talking about two different things regarding one of your earlier posts about a correction factor.

what i meant was that if you measured your DO in your brackish tank at 80F on a mountain and got 5ppm DO then no correction is needed becasue thats what the meter has measured.

A correction factor is only used to work out the saturation point (max DO possible)

OR

if your meter reads in % saturation (keeping in mind that many meters will already correct for temp, so altitude is the only correction factor to apply in this case)

Again you have a good grasp of it all.

All you need to find out now is the DO required for breeding of crays, if its below 5ppm then you're set

I know yabbies will survive is horrible DO levels, but wont breed

lol, ah ok. Yes, what the correction factor would be used for, would be to determine the saturation point of DO possible of a body of water at altitude or temps. As you just pointed out, it's a good way to determine the feasibility of a project. I know the optimum level for redclaw is 6ppm.

Now the next question on DO saturation is HOW do I 'SUPER' saturate it?


oh Steve, and as an Admin, how would you feel about splitting off the DO discussion from this thread, I'm sorry, I kinda hijacked it.

can do, is there already an applicable thread going?

I don't know. I don't recall one that focused on DO. And it may just be me, but I would think it's important enough to deserve it's own thread.

anyone else know of one?

On the topic of both this thread and the hijack...

What are the methods to Super saturate water with DO? I know of using pure oxygen and oxygen contractors. But any more reasonable methods for the DIY'er?

If not, twintragics,
Could you ask the prof?

Rassd,

Was just looking over the table you posted again, and it still doesn't make sense to me!

It says to correct the ppm of the sample taken from the lake by the correction factor.

the ppm of the sample is the ppm of the sample!

AM I MISSING SOMETHING???????? please help

rass, we spoke a bit about ozone last week. I think in it's elemental form it acts as a killer of nasties in solution, but at too high concentration can cause gill/respiratory issues. It then breaks down to oxygen, so u get 2 bangs for ur buck. I don't know much about it, it was just mentioned in passing. It is a highly reactive gas and needs handling with kid gloves.

In a pond environment, a paddle wheel is the easiest most cost effective way to go. In recirc, i really don't know.

some one pointed out that brakish (salt) water has a lower Do cause of its higher density due to the disolves solids already present

this would mean to me that if you wanted to super saturate the water you should think about removing some of the other dissolved particles (atoms Ions whatever) easily done using Ion exchange deminralisers or Revers osmosis

but with these sort of systems you will remove most of the minerals and goodness from the water leaving you with alomst pure H2O this could cause other problems on teh plant side of things not too mention that anything not 316 stainless glass or plastic would be extreemly vulnerable to excerlated corrosion

hmmm reading that gain im thinking i put forward an idea and dismissed it in the same post .... maybe i should just be quiet

i think supersaturate means to have a higher than saturation point regarless of what that saturation point is.

Steve,
Thanks for making this it's own thread.

As for the altitude correction and the MEASURED amount, I'll have to do more research, because I too am confused. I know most DO meters have to be set to the altitude, but I would have thought that once that was done, measured DO would be measured DO. hmmm.

I have seen brief mentions to Ozone being used, but haven't seen any small scale examples of it. Only the super high intensity systems where they are also using pure oxygen.

Paddle wheels are still the most common aeration method used from what I can find. With airlifts being the next best option. Air diffusers or bubblers are really only good in deep systems with tanks or ponds at least 10 feet deep so the bubbles have time to stay in contact with the water. The one nice thing about bubblers is that the help to de-stratify the water column.

I think I'll have to approach this the way I do most things, learn as much as possible and then just experiment with it to prove it to myself!