For those having continous algae problems

Eric Borneman did a salt test awhile back.  I asked him to summarized it & here is the respone I got.






Sure - this was a while ago and I never wrote it up because by time I got around to it, new salts were out and it became obvious there were batch issues. Basically, we took ten tanks and used nine salts plus natural seawater, used clonal fragments of various corals, algae, corallimorphs, a clownfish from the same brood in each tank, sponge, snails, hermit crabs, etc, sterilized sand, 0.22 micron filtered the water, checked water chemistry after 24 hours of mixing, weighted undissolved materials and examined under a scope. Tanks were in a climate controlled room, same water flow, same lighting, etc.
Every month, we changed 100% of each of the tanks' water with a new batch of the same salt for 12 months - separated and purchased as far apart as possible geographically, in time, and in container size to try to get different batches. We measured growth by either dry or buoyant weight, polyp reproduction, linear length, coralline algae, other algae that was not a measured variable, any other growth, plankton counts, any reproductive events, and any mortality. At the time, Red Sea and Reef Crystals had the least mortality and the best growth of all the tanks, exceeding even the natural seawater tank, especially in terms of coralline growth. Six other salts fared roughly equally, with some growing some things better but also faring worse in other areas. The two that performed the worst were original formulations of Crystal Seas (although new formulation did fine) that flat out killed things, and Instant Ocean. Instant Ocean month after month had organisms with slow declines and grew filamentous algae and cyanobacteria consistently throughout the twelve months. It was consistently bad. The other salts went through algal successions like normal tanks and had outbreaks of filamentous and cyano for a few months - around months 3-5, but then started growing corallines. Instant Ocean just ket growing hair algae, cyano, and organisms generally slowly faded away.
That said, I have used IO for years at a time with no noticeable deleterious effects and there is no doubt many others do as well, and breeding fish occurs in IO, and successful reef tanks use IO. But, in a low diversity controlled test, the results were very clear. I suspect that full functioning systems compensate for the effects we saw by mitigating them through diversity and the technology/filtration, etc. used. The problem with all the salts was the highly inconsistent nature of them, and so based on what we saw, it's kind of a crap shoot if you get a standard good batch. Some salts had less variation than others, but all had variation. It still doesn't take away that IO consistently performed poorly in our tests.
The thing is, if you were to price even large quantities of the lowest grade lab quality salt - just reagent grade or technical grade, the cost of a bag of salt would be too high for anyone to afford, and some of the salts used, like mag chloride, are notoriously "dirty" even when a high purity salt is purchased. So, we are left with companies that, because of volume needed and cost, must source materials by truckload, bargeload, and commodity pricing from various sources that may be from ore or other resource. This would explain the variability and the effects we saw. All said, though, some of the synthetic salts fared just fine compared to natural seawater.
One last caveat on NSW. This was either NSW from the Texas A&M cephalopod research center and then filtered and evaporated to seawater salinity or collected from 100 miles offshore in oligotrophic water and filtered to 0.22 microns. NSW from coastal areas may not be the same at all and may be very bad to use. Also, NSW is no longer ideal water in terms of growing corals with pH and carbonates below historical levels and below those of many synthetic salt mixes.
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Eric Borneman

 

Copied with his permission BTW

 

Also here is an exerpt for anyone using rubbermaid cans for water storage

During our annual spawning work in Puerto Rico, we had one night where we collected about 600,000 gametes. On putting them under the scope, we found that sperm motility was bad to none. Hence, fertilization was very very low. This was very unusual. Over the next few days of development, many of the fertilized eggs had arrested development, abnormal development, died, or underwent embryonic fusion.

Since a major focus of the work was to cryopreserve sperm for genetic banking, we quickly wondered what could have gone wrong. I had purchased the standard grey Brute trashcan that almost everyone I know uses (you can put rollers on the bottom). When rinsing it, the water beaded on the surface but it was rinsed well and wiped with DI water. Nonetheless, the egg bundles were kept for experiments in 0.22 micron filtered water taken from that trash can that itself was filled with 0.5 micron filtered NSW.

Upon adding tiny amounts of this water to sperm acquired from another source and not exposed to the water in the trash can, the sperm became immotile within minutes.

Basically, the plasticizers in the trash can are highly highly toxic to sperm. Another group had a similar experience using new plastic containers (not the Brute trash can) on another night but did not test or have available healthy sperm to check for plasticizers being a cause.

The point here is that for all of you (including me) who use plastic containers, and definitely the almost industry standard" grey Brute trashcans to store water or kalkwasser, have highly toxic plasticizers. We do not know if these would leach out if soaked, exposed to UV, acid-base washed, if it is a coating, or impregnated. But, at the very least using water from these containers, definitely when new, will cause reproductive failure and who knows what other chronic effects it may have.

Some of you may be saying - as I have - that you have used them for years with no problems. Well, no problems you can directly find or can observe. It's like our test with Instant Ocean salt mix - I used it for years with no apparent issues, but in a controlled experiment, it perfomed terribly, caused chronic cyanobacterial films, and species died. Perhaps the resilience of healthy diverse tanks mitigates the issues, but when used alone, the effects are obvious. Perhaps the plasticizer is a new one, or perhaps it leaches out in time. We don't know.

I have posted a photo of the offending trashcan. Beware all plastic products that are flexible and that bead water when wetted.



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