i have this plant and i dont know what is happenin...

probably 2 tbsp PH down per gallon of water

What can i use then to lower Ph? I have no Ph meter or stips and using bottled water with 7ph.

Your having ph issues, 7.0 is too high for the plant to properly intake the nutrients it needs. Try getting it between 6.0-6.5, this a perfect range to ensure the plant is getting its proper nutrients.

Personally i use a ph of 6.5. Reasonable light like 250 watts at about 18inch away. If after a few more days you notice no decent growth start to use something like forumlex. At a very weak strength and everything should be all good mate.

you have pH fluctuation because the soil pH is lower than the water pH so it's making problems, you should try watering with water around 6.5 or 6 pH, just adjust it over time so the new pH is not a big shock to the plant. Hope this helps ! 🚀