Culture Journal, Species: Oxyrrhis marina

Hi Jim-
 
ClorAm-X is wonderful stuff, in fact it is the key to high-density rotifer cultures, but it is possible to misuse it. The preferred method of use is to measure ammonia, and dose accordingly.
 
Contrary to the statements of the manufacturer (and not surprisingly), we have found that it is in fact possible to overdose and inhibit the growth of rotifers, and no doubt other animals. This has happened when users have blindly thrown in ClorAm-X in reaction to finding a high level of ammonia in their cultures. For rotifers inhibition becomes evident at about 0.3 g of unreacted ClorAm-X per liter of culture. Of course you can put in more ClorAm-X than this, as long as there is enough ammonia to react with it and “use it up”.
 
But nobody wants to have to measure ammonia every day. We have found that our continuous rotifer cultures are stable and predictable, and we have learned that for a given feed dosing we need a certain dosing of ClorAm-X. For other culture systems the dosing is likely to be different.
 
But here is a rule-of-thumb to start with:
 
Rotifers, at least, can be expected to convert about half of the nitrogen in the feed to ammonia (the rest goes into rotifer proteins). Our algae pastes are all about 50% protein, on a dry weight basis. The dry weight of the paste is roughly half of the first 2 digits of the number in the Instant Algae product names, so Nanno 3600 is 18% dry weight. It works out like this:
 
Nanno 3600 is 180 gm per liter dry weight X 52% protein X 16% nitrogen in protein = 15 gm/l nitrogen = 18.2 gm ammonia /l = 18.2 mg ammonia /ml. But if only half the nitrogen goes to ammonia, then 9.1 mg ammonia/ml of Nanno 3600 will be produced.
 
Dosing formula is 31.9 mg ClorAm-X to neutralize 1 mg ammonia, so you would need to add 290 mg ClorAm-X per ml of Nanno 3600 that you feed, or 290 gm/liter.
 
But this is a “worst-case scenario”.  Could the protein conversion rate be better than 50%? Will your animals eat all the algae? Are you removing a lot of solid wastes from the culture (this removes some nitrogen)? If you do a 25% water change, it removes 25% of the ammonia.  The natural bacteria in your cultures will convert some of the ammonia to harmless nitrate.
 
So to calculate your dosing, first consider the dry weight of the feed you are using. For our non-Instant Algae feeds: Rotifer Diet is about 5% dry weight, PhytoFeast is about 2.8% (we thin these out because the Instant Algae pastes are too thick to be accurately dosed in the very small amounts of biomass that reefers should add to their tanks in one feeding).
 
Your suggested dosing of 12 teaspoons for 1 liter is equivalent to 60 g/L (1 tsp = 5 gm).
PhytoFeast would take 45 g/L
Rotifer Diet would take 80 g/L
 
In theory!
 
Really the practical safe ClorAm-X dosing can only be prescribed in relation to the ammonia load, which really must be determined by testing. This is especially true if you dose ClorAm-X day after day and only do partial water changes—this can allow an excess to gradually accumulate to inhibitory levels.
 
Of course nobody wants to waste money either, also a good reason for not using more than you need.
 
We have seen no evidence that ClorAm-X solutions break down chemically, but the less concentrated they are, the more likely that fungi can grow in them. Refrigeration is a good idea in any case. I suggest that you not make up more than you can use in a couple of weeks.
.
 
 
 
Eric C Henry, Ph.D.
Reed Mariculture Inc.