Bacterial supplements are meh, they don't really seem to work right...
I don't think you need to do 50% everyday, i would do 25% everyday or 50% two or three times a week. If the tank is cycled you should only need 1-2 50% WC a week. If its not, then you want a little Ammonia in the water so it can cycle.
So if you have ammonia, it isn't done cycling. If you have Nitrites, isn't done cycling. If it isn't done cycling then it needs a bit of ammonia to cycle. So you don't need to do such massive, frequent WC.
0 Ammonia, 0 Nitrites, and have some amount of Nitrates means its cycled.
And it doesn't mean your terrible to not have a Test Kit.
My little secret... I don't have one either, at least not a full one. I can test the PH and Nitrates. If i want the rest, i go to the LFS, say "Im not buying fish today" and ask them to test it. But, PH and Nitrates and Temp are the only common things that you need to test for in a cycled tank. And my fish do ok.
Sent from my bed, the only space available to me that isn't smothered in dirty laundry or aquariums.