advanced higher biology project

Hello,
For my advanced higher biology project I am investigating the effect of concentration of alcohol on th heart rate of daphnia pullex, this is my method
Place the Daphnia in a small drop of water in a petri dish using a few strands of cotton wool to restrict movement.
Allow to acclimate to new surroundings (record every 1 minute) until heart rate stabilises, count and record the baseline heart rate in the control water (control measurement), with the light of the microscope off. Repeat 3 times for the same daphnia and calculate an average for accuracy.
Only add ethanol once the heart rate has stabilised.
Using the edge of a paper towel to carefully remove the majority of the original water.
Immediately add the prepared ethanol solution to submerge the Daphnia (use the same volume of fluid for each test)- 5 drops of pipette.
Wait a specified time for the Daphnia to acclimate (determined in pilot study). This allows an effect to occur, measure when heart rate stays constant (measure heart rate every 30 s)
Using a light microscope, record the heart rate for 15 seconds and then multiply by 4 to find beats per minute.
Repeat for each concentration 3 times, and then repeat at different concentrations. For each concentration measure the heart beat stabilised in water before adding ethanol.
Use a different daphnia for each repeat and place used daphnia in a different tank.
Before using ethanol make sure to repeat the experiment 3 times with just culture water to determine a control.
Any suggestions or improvements would be really appreciated.
I am wondering before and after exposure to ethanol when the daphnia are acclimatising do I only record heart rate once its stabilises, or do I record every 30 seconds until it stabilises. And after exposure and after the acclimatisation time how do I know when the ethanol has had its peak effect on heart rate.
Thank you

Your method looks solid overall, but here are a few suggestions and clarifications.
Recording during acclimatisation: record the heart rate at regular intervals, such as every 30 seconds, until it stabilises. This gives a clear picture of how the heart rate changes and shows when it has truly stabilised. Do not just take a single measurement.
After adding ethanol: the heart rate might fluctuate at first, so continue measuring every 30 seconds or every minute until it reaches a plateau. The peak effect is when the heart rate stops changing consistently and remains roughly constant for a few readings.
Other improvements: keep the same temperature and lighting for all tests to avoid external effects on heart rate, use realistic and safe ethanol concentrations, randomise the order of concentrations to reduce systematic error, and use a stopwatch to standardise acclimatisation and measurement periods.
Measuring at intervals until stabilisation before and after adding ethanol will ensure accurate and reproducible results.

Thank you very much that is very helpful

I have a few more questions, if anyone has a minute to answer please.
In one of my pilot studies to determine appropriate concentration of ethanol solutions I am planning on testing 0%, 2%, 4%, 6%, 8% and 10%. Are those okay and if so how do determine a safe range for actual experiment.
How is it best to control temperer and light when conducting my experiment?
And is this an appropriate method to determine sample size?
Thank you very much

At the moment I haven't actually begun my pilot study so I have no results but thank you so much for the offer. Your help is so appreciated and has answered many questions!!!