Starting PH is 8.2, I added 1/4 teaspoon PH down to 4.5 gallons tap water and dropped PH to 3.7. Does that seem reasonable?
Yes. That's far too much. A single drop of that stuff would be about right. 2 drops would be too much. You need a 1ml dropper to get very small drops, or if you aren't good at dropping single drops you can pull 1/4 ml into the dropper, then fill the rest with plain water to dilute the PH down, then use the diluted solution instead of straight up PH down. AN's PH up and down is highly concentrated.
Never used that brand before and when he said it dropped the PH that much it almost didn't sound right until I looked up and read what you said. Its really concentrated probably more practical for larger amounts of water and or nute mix like in a 50 gallon res. But another way to look at it once you learn how to use it well with your water and or nute mix you wont need to buy anymore for a long time. http://www.420magazine.com/forums/grow-supply-product-reviews/166276-advanced-nutrients-ph-down.html
Yeah I'm not a AN fanboy or anything, but their PH products are the best out there imo. My experience is the same as that guy's you linked to. Even for relatively small grows it still saves money in the long run.
Well that's good to know. I had PH down from another company and the instructions were clear; .5 teaspoon per gallon to drop PH by .5. AN doesn't give any instructions except to test PH, add PH down, test PH, adjust as needed. I (stupidly) assumed it would be similar to the other product. I now have a digital PH meter, but I'm relieved I didn't kill my plants.
In 5 gallons you need about 1/8 to 1/4 ml or so of AN PH down to go about .5 down. So it's about 10 times more concentrated than that other brand, but it's not all that much more expensive. Definitely a good product.
changing ph has to do with how many buffers are in your water...thats why straight ro water takes a drop and water with nutes takes a lot more...a general application rate doesnt really apply
He said tap water. It probably has a few hundred PPM. AN still only takes drops even with nutrient water. In 5 gallons 1/8th of a ml is only like 5 drops or so.
Yeah I run flood and drain so I need it. Other brands take way too much after the res has already flooded once or twice. The PH goes way up.
Today, I checked PH before and after adding Tiger Bloom and Big Bloom. The PH dropped from 8.2 to 6.3 with no PH down! I guess I needed the PH meter about 2 months ago.