DSB testing

[loganj]

OK, I've posted about this before and didn't get much in the way of feedback so I'm going to try it again. I'm going to start pulling samples from the DSB in the 180 reef and sending them to Analytical Labs in Cleveland, TN. What, in your opinion, should the samples be tested for? I'm going to have a total metals done on the first sample to establish a baseline for further testing. Unless I'm mistaken, the prevailing theory is that metals are building up in the sandbed and this causes OTS...usually at about the 5 year mark. Are there any other tests that should be done? My intention is to pull monthly samples for testing and graph the results. I realize this isn't really a scientific approach that will prove or disprove OTS, but it should give us an idea what's going on in our DSB's.

An interesting note: GAC will remove metals from water to a certain point. Once the metals reach a saturation level, they are released back into the water in large quantities. So, if you use carbon, change it regularly.

Another theory that perhaps doesn't have as much support is that something is causing a mass die off of the bacteria in the sandbed and this poisons the tank. Any opinions/suggestions are welcome. Testing will commence in May.

 

[BillyZ]

Nifty! I find this very intriguing. I'm going to just spit out a brainstorm here. (and random questions) I'm not a chemist however so I'm working on ignorance here (it's never stopped me before )

I would send a sample of the water column itself to provide a comparison between the water and the DSB.

I would say the metals test as well as... ack... brain fart... what's the gas bubbles that build up, sulfar dioxide? see if thats remaining anywhere in substrate itself.

Can you do a general toxins test?

How are you planing on taking the samples?

I would think you would want to be able to take a sample without introducing much of the water column into the DSB when sampled.

How deep is your DSB? Is it possible, would it even make a difference, to take a sample that maintained the structure of the sample? In other words the sand on top remains on the top of the sample and the sand on the bottom remains on the bottom of the sample? It could provide additional info.

I would take multiple samples from the DSB in different locations in the tank. Water flow over the substrate is commonly believed to be important to a healthy substrate. If you have various flow rates over your substrate your tests may help prove or disprove this.

I'm looking forward to seeing what results we get. And if it would help would be willing to take and ship a few samples myself (whats this going to cost?). What kind of lab will you be sending them to?

sorry for the rambling... like I said, brainstorming.

 

[Biggen]

I honestly can't think of anything else to test other than toxic metal buildup. Are you going to have to give them a list of the metals (i.e. copper, alum, etc...) or do they have standardized tests that will test for large quantities of them?

An interesting note: GAC will remove metals from water to a certain point. Once the metals reach a saturation level, they are released back into the water in large quantities. So, if you use carbon, change it regularly.

I am not too sure if I agree with this, Logan. I was always under the impression that carbon can not de-absorb in the aquarium. Here is what Dr. Tim Hovanec of Marineland has to say on the subject:

DE-ADSORPTION

De-adsorption is another phenomenon that is over-stated in the rumor mills about activated carbon. Again, it is an incomplete statement that is commonly used to described the process. It goes, in one fashion or another, as: don't use carbon because once its adsorption sites are full it will release, or de-adsorb, all the stuff it has adsorbed releasing a large amount of pollutants back into the aquarium. The implication in this sentence that activated carbon works something like a capacitor such that once at its maximum adsorption capacity, it instantaneously discharges all the bad things it has adsorbed is wrong. Carbon does de-adsorb, in fact, that ability is exploited for recycling precious metals. However, in a controlled industrial process, the quick release of the target substance is accomplished by switching the pH of the water. The basic process is to capture the target substance at one pH extreme (very acidic or basic) and then reclaim the substance by switching to the other pH extreme. As stated earlier in this article, these pH values are outside the normal range of aquaria. De-adsorption is not a process to be worried about.

Source: http://www.marineland.com/articles/17RevisActCarb.asp

 

[loganj]

My source was the guy at Analytical Labs who claimed they had tested GAC to see how well it would remove metals from water. We didn't get into all the details, but he did say that, at a certain point, large quantities of metals were released back into the water. I don't know if this corresponded with a change in pH or not.

 

[loganj]

I'm working on ignorance here (it's never stopped me before )

Never stopped me either 8O

I would send a sample of the water column itself to provide a comparison between the water and the DSB.

Good idea.

I would say the metals test as well as... ack... brain fart... what's the gas bubbles that build up, sulfar dioxide? see if thats remaining anywhere in substrate itself.

I think it's hydrogen sulfide and I'll see if it can be tested for. I wish I knew a way to determine exact O2 levels at different depths in the sandbed. The hydrogen sulfide occurs in, if I'm not mistaken, totally anaerobic areas as opposed to the anoxic areas that will produce nitrogen gas.

Can you do a general toxins test?

I don't know...I'll check into it though.

How are you planing on taking the samples?

What I had in mind was to use an open glass tube about .5" in diameter and push in all the way to the bottom of the sandbed. Then seal the top and pull it out. This should give a total top to bottom sample of the sandbed. I'm open to ideas here though.

How deep is your DSB? Is it possible, would it even make a difference, to take a sample that maintained the structure of the sample? In other words the sand on top remains on the top of the sample and the sand on the bottom remains on the bottom of the sample? It could provide additional info.

The sandbed is about 6" deep. I don't know if I can reliably separate the sample in a way that will maintain its integrity or not...would be something to look into.

I would take multiple samples from the DSB in different locations in the tank. Water flow over the substrate is commonly believed to be important to a healthy substrate. If you have various flow rates over your substrate your tests may help prove or disprove this.

True. I intended to take the samples from different places each time. The tank is a 180 with about 3000gph flow so I think most, if not all, of the substrate is receiving good flow. Once I learn a little more about this, and get the tanks going in the greenhouse, more testing may be possible.

I'm looking forward to seeing what results we get. And if it would help would be willing to take and ship a few samples myself (whats this going to cost?). What kind of lab will you be sending them to?

Sure, if you want to...that would be great. I'm sending the samples to Analytical Labs in Cleveland, TN. They do a lot of industrial testing. The impression I got was that they weren't going to charge for the tests as long as I didn't get too carried away with sending in samples. The lady who is over wastewater treatment at the chemical company where I work is going to help with sending the samples off and getting the results.

sorr

 

[reefrunner69]

Have him test for PO4 organic and inorganic.