no the whole point is that .25 is the lowest they read, so, they lie. the API tests. terrible

makes us take unneeded action awaiting a zero reading that will never come. you already had zero ammonia long ago
the prime was never needed but harmless to use if you like. search reefcentral and nano-reef.com to see others results: "API reads .25 always?"
heres one
http://reefcentral.com/forums/showthread.php?t=2287316
nano-reef
http://www.nano-reef.com/topic/326719-ammonia-help-read/
one of the keepers here likes his API and says no problem. I imagine most of the problem is color referencing.
Im starting to collect these threads in myblog. after I build up 200 or so I plan on making a writeup and asking the company to comment. there is only one time that API test kits for reef tank ammonia are helpful. Thats when they turn solid green to indicate a loss of something huge like a fish. For low level readings, you should be relying on predictive biology regarding in-tank generation...for outside sources like sourcewater concerns, use a different test kit to monitor your filters.
I barely started collecting these threads but my post history would show about 2 years worth engaging and over 200 times easily. thats not even counting nano-reef.com, add another 200 there.
hunting these threads down is kinda fun. Nearly any thread in here that mentions an ammonia problem is using API and therefore has no way to know if they have a problem. eventually someone is going to shoot down my API prediction with "sorry, salifert" then what will we do lol
I used the analogy the other day that using API ammonia test kits for marine tanks is like using a antenna rod as a dipstick in your car and trying to make a reading off having "some" on the rod.