There is a bit of history that will put things in perspective:
The first generation of AS (3-4 years ago) would leach a LOT, and it also had high organic content. ADA was also pushing PowerSand and THAT just added more junk. Frequent water changes with that version of AS was the most practical way to keep ammonia below 4 ppm.
The latest version of AS (about a year now) leaches a LOT less. If you plant a lot of plants from the get go, not changing the water saves you labor and $2 on ferts.
The last 3-4 tanks I did with the new AS I did not bother with WC fir the first 1 - 2 months (depending on volume of AS to volume of water).
Ammonia much above 4 ppm is not good for much besides cleaning windows, but can and will burn the leaves and kill our precious bacteria.
Hmm...well the AS to water ratio is pretty high... About 2 liters of AS to 5 liters of water. It's in a fluval Chi and fairly deep. My ammonia is at least 8ppm, maxing out the API test. If it wasn't maxing out, I wouldn't be worried about it, so that's why I posted.
Also, ammonia at this acidic pH is more ammonium ions which as I understand are significantly less toxic than the neutral ammonia that persists at higher pH. The pKa of ammonia is about 9 in water, meaning at pH 9 there would be a 50:50 mixture of ammonia (toxic NH3) and ammonium (NH4+). So assuming the concentration is 8 ppm total, then at my pH of 6, drifting to 7 when CO2 is off, this means my ammonia concentration during the day is about 0.3 ppm while at pH 7 it's about 0.8 ppm. Hurray science!
So I suppose it would be best to just do a water change, especially since it's such a small tank, until my ammonia level actually registers below the max.
I think there's already plenty of ammonia around to keep the cycle going after the water change.
You talk about ferts...should I go ahead and dose potassium and phosphorus while cycling and pumping CO2? Pardon my ignorance, I've never actually set up a tank devoted as a higher tech planted tank from the start.