The raw shimp thing is very old school S/W and you really want to shy away from it now (it has to rot to create ammonia, you decide).
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The ammonia can also be purchased from a pharmacy. (just don't make jokes about a 'meth lab'

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In the beginning there was water...then the water begat fish and fish begat ammonia and then nitrosomonas begat nitrIte and nitrobacter begat nitrAte and W/C's begone nitrAte.
or
The fish excrete ammonia thru their gills and and waste products along with decaying food particals.
As ammonia builds (toxic to living creatures), nitrosomona bacteria begin to breed in the filter and everywhere, feeding off the ammonia, or oxidizing it and in turn creating nitrItes (also toxic to living creatures) and as before bacteria (this time nitrobacter) oxidizes it to create nitrAtes (not as harmful to living creatures) which we remove by doing water changes (w/C's).
These (ammonia, nitrIte, nitrAte) are monitored with a good quality (fresh) test kit.
The ammonia to nitrIte part takes ~ 1-2 weeks. You will see the drop in ammonia as the nitrItes rise with your test kit.
Now start watching for the rise in nitrAtes and the drop in NitrItes.
NitrAtes will shoot up and ammonia and nitrItes should zero out, then its time to do a W/C and it's good to go.
At the end of this procedure the guinea fish are very stressed and can develop diseases or just flat out die.
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Using 100% pure non-sudsing / additives ammonia. (note household ammonia is 4-10% were as pharmaceutical grade ammonia is ~28%).
Add drops of ammonia (usually 3-7 this can vary with your water pH) to the tank till you get a reading of 5 ppm. Keep careful track of how much you added you've used so you can repeat this process daily. Once you can detect nitrites you should only add about half the drops of ammonia you were using. Continue this process daily until you get nitrate readings with your test kit. Do a 30% W/C and the tank should be good to go.
You will notice no fish were harmed in the above process.
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There are some cheats, as in adding media from an established filter known not to have any diseases (how well do you
really trust your friends or LFS?).
Or adding Bio-Spira (living bacteria).
Or as some have done here, just create a miracle.
Keep us posted,
Dr Joe
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