of course it doesnt stay stable.. PH down doesnt even stay stable.. lemon juice is just a home remedy.. ph down is the real deal.. but like i said it doesnt even hold stable over time.. i have to use it every day in my res to keep my ph stable... it really just makes you look like a jack ass when you say "your gay when you use the wrong thing"... and further more, even if the lemon juice doesnt hold the ph down as long as real ph down, it worked right?? it still lowered the ph.. which is what it is said to do... so if it was said to lower the ph and it did lower the ph it really isnt the wrong thing is it?? maybe not the BEST thing.. but not the wrong thing.. the wrong thing would be something that raised the ph.. so just another way to look like a jack ass..