Yea if it continues it will worsen . You do the calculations F to C .
You need it 62f best for oxygen absorb to 70f or chance root rot .
You can change the water daily and still get root rot or add beach chemicals still root root .
What you can do. Get a few bottles throw them in the freezer . Toss them into the water change when needed every 12 hours ? Whenever needed . The big boys buy water chillers its nothing you need to get with a plant or two chillers are not cheap 500 up.
Chillers have ac built Those chillers with just the fan will only cool the water a degree or 2 waste of cash .
What i see right now if you got your water under control you are good to go .
You can make a chiller out of a window ac unit take it apart. Take the unit in front bend it into water .
I build more then a few water chillers i could chill 1000 gallon of water for under 300 24 btu ac unit . You get the point after watching the video . Buy a used window ac unit for 20 a 5000 btu more then you need . Get a thermostat digital that turns on and off the ac . Done deal . Few hoses a pond pump