Has my tank finally cycled and what’s up with my PH?

[Betta Love]

Hey guys I have been cycling my tank for almost 4 weeks now and checked on my ammonia nitrites and nitrates today and got these results does this mean my tank has finally cycled? I’ll post what I had last week and what I have now first pic is last week second is now and if it has finally cycled before adding fish should I do a water change? And how much. Also my PH at the beginning of the cycle was at 7.6 and now it’s 6.0 I remember it had dropped a couple weeks ago so I put in baking soda and it worked for awhile. I also have these weird floating white things on top my tank water any idea what this is? Thanks!

 

[Colin_T]

Add enough ammonia to get the level to 2-3ppm and if there is 0 ammonia and 0 nitrite in 24 hours, then the filter has cycled.

If it has cycled, do a 90-100% water change using dechlorinated water. Wait a couple of days and then add the fish.

The pH has dropped because the filter bacteria use KH (carbonate hardness) to grow. When the KH runs out, the pH drops.

 

[Betta Love]

Add enough ammonia to get the level to 2-3ppm and if there is 0 ammonia and 0 nitrite in 24 hours, then the filter has cycled.

If it has cycled, do a 90-100% water change using dechlorinated water. Wait a couple of days and then add the fish.

The pH has dropped because the filter bacteria use KH (carbonate hardness) to grow. When the KH runs out, the pH drops.

Alright thanks!