DSB Heresy

I intend on using a modified version in a shallow sandbed, that is only used for occasional draining of the SSB to try and keep it cleaner than just stirring it up. Anyone else tried this yet? (if this is already posted in this thread please indicate the page if you can find it)
 
Why the objection to water changes? Water changes dilute the toxic metabolites that are produced by most corals. Your system does not address this issue.
 
MarkS said:
Just bringin' this back from the dead.
Thanks Mark!
I havenââ"šÂ¬Ã¢"žÂ¢t seen this one before!
Just subscribed to the thread, so I can go through all the pages later on.
 
i know a bunch off people have tried it however no response on its long term fesability no ones gotten back to it i guess there useing it havent heard anyone post that it dosent work lol but since there's no response no way of telling
 
System with redox control

System with redox control

Please forgive me if I'm about to say something stupid but as I remember, the de-nitrification process happens in a certain redox band, if there's a higher redox potential, oxygen is available for the bacteria and nitrification happens, lower and the bacteria start processing sulphate to produce hydrogen sulphide. So couldn't a system be run with a redox probe controlling a dosing pump to keep the plenum region at just the right redox potential? I know that this destroys the 'flushing' effect but surely would manage things more accurately. Anyway, I'm new to this - that's my excuse, just a question / idea that crossed my mind.


All the best,

Keith

PS Sorry, the original article is concentrating more on flushing waste, I'm thinking more of managing it. Wouldn't too much flushing lead to the wrong conditions down there though, so some sort of probe would be useful to judge when a flush was appropriot?
 
Well the idea is there, however in real life, there tends to be channelling through the sand bed, so where the probe is may not be an accurate reflection of the overall redox of the bed.
Probably the best way would be to measure if the system is performing as required in terms of actual tank water quality, and adjust flow rate according to that. That's just my thoughts anyway.
 
Please, please, forgive me if I ask something that has already been asked and answered before...

I stumbled across this thread today at work and have done my best to read through as much of the 21 pages as I can, but still have some questions regarding a CPW setup...

Let me first say this. I'm not a chemist, not an engineer, not a Dr. or a biologist. I failed chemistry in high school (only subject I ever failed), and wasn't very good at math (though I managed through that somehow). I studied history in college. So everything I've learned in this hobby has been a struggle. :)

A bit uncertain on this point; why can't we use sugar-fine sand with a CPW? Is it because even with the tiny 1/32 holes and several wrappings of the synthetic fiber over the system we'd get clogs and drain out a bunch of sand?

I like the idea of finer sand vs. crushed coral for aesthetics and all the cool critters you can grow/keep in it. Not to mention that many corals get fed by the stuff that comes up and out of a DSB.

Which leads to my second point of confusion:

Say you can run a CPW under a DSB (5-6 inches) of sugar-fine sand. Will you, by draining the mystery waste out of it, also eventually leech out some of the microscopic critters and good stuff from your sandbed?

Last, if you have a CPW or not, do you want to stir your sandbed a bit now and then to prevent solidification of the sand?

And I too wish we'd hear from ldrhawke to see how his setup has worked over the year he's implimented it.
Thanks to anyone who can answer these questions!
 
I would like to add By keeping your sand bed limited to 2 inch's you'll sucessfully reduce sulfide toxins from your tank. The only negitive feedback is you'll have to deal with nitrates in another way.

After 2 inch utliztaion of nutriunts by bacteria drops off HEAVLY
It talks up alot of tank space is really dosen't do much.

It Seems Everybody Is Giving DBS a Bad Wrap But I Dought Tanks That Ran Into Problems Where Matained Properlly.

They require ROUTIEN additions of new infunna kits.
 
Like as40, I am not enough of a chemist/biologist either to understand what is going on with DSBs though I think I understand the general concept. Please correct me where I go wrong.

It appears that the trapping of waste products in a DSB is the concern. If you keep enough critters in the DSB they naturally stir up things and allow a safe and slow release of this waste into the water column where it can be removed through conventional filtration methods and thus prevent the accumulation of those waste which will lead to generation of some toxic compounds. The key here being that the critters must be in such abundance that they keep the DSB pretty well stirred up. Apparently the critter population diminishes through natural causes (die, become food, etc.) and must be added to in order for them to remain effective.

Is there a rule of thumb for their replenishment? Say you put in X amount of them. How often and how many (portion of X) do you need to add?


Another thought from my FW planted tanks. Dupla promoted the idea of low voltage undergravel heating cables for planted tanks. Their claim was that the cables, evenly spaced over the bottom of the tank, created natural convection currents that caused the water around the cables to rise into the water column and brought fresh water from the water column down into the substrate. Many in the FW world question the effectiveness of this in helping plants to grow but even many of the dissenters admit that they might be a solution for the long term survival of the substrate. It has the added benefit of providing a hidden heater for the tank though this is not an issue when you have a sump. But I will say that the heating control I was able to maintain with undergravel heaters was a far tighter tolerance than I ever observed with a standard heater and it took far less wattage to do it.

I will say that I used them with a 3-4" bed for 3-5 years and never had any trouble. Plants grew like crazy. What gassing I observed when disturbing the bed (planting or aquascaping) was odorless - absolutely no sulfur smell. My first planted tank did not have heating cables and I know the odor well. I would add that my life has been incredibly busy the past few years and my tank maintenance has suffered for it. So build up of excess waste was frequent. On top of that I was dosing the nutrients you guys try to eliminate (NO3, PO4, etc.) to encourage plant growth. I had a glass at the end of the tank break and had to quickly change out to another tank (fortunately had a spare). I had to use a lot of the gravel from the existing tank and noticed no odor nor any harm to the fish.

Has anybody ever tried this?

Thanks
Charles
 
the concept makes sense to me, at least to some degree. what i have been wondering is could you just have a bulkhead on the bottom which you could just open up a valve every once and awhile and basically do a water change through the bottom. you would be flushing the sand out from the bottom so that very little waste ended up in the water. would the aggressive flushing ruin the operation of a DSB? would this be equally effective on a shallow sand bed?
 
chask said:
Another thought from my FW planted tanks. Dupla promoted the idea of low voltage undergravel heating cables for planted tanks. Their claim was that the cables, evenly spaced over the bottom of the tank, created natural convection currents that caused the water around the cables to rise into the water column and brought fresh water from the water column down into the substrate.
Good point on the convection currents through the substrate! I donââ"šÂ¬Ã¢"žÂ¢t think it would help much under where you place your LR, However under the open areas of the tank it would probably help?
 
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