Clean the cloner real well with a bleach solution-- INCLUDING running it with the bleach in in (no plants obviously! Just the plugs if they are used ones)
Then rinse well and run 2x with plain water to get all the bleach out and let air dry overnight.
Use BOTTLED water-- you can usually get a 3-gallon jug of "purified drinking water" for around $2-$3 USD... then add a tablespoon of peroxide. Make SURE your air pump is working full-force and change the air-stones (they harbor algae spores!)
Run the system for at least 6 hours before you test and adjust the pH-- then wait 3 hours and test it again...
Turn off the pump, open the lid, and smell the inside... does it smell clean? If not-- go thru the entire cleaning routine again....
Now-- check your foam plugs. Will they be tight, or loose around the stems? If tight when down in the cloner- Hold each one "open" and snip away a small piece to create a small opening for the stems...
Now-- run the pump for a few hours- then turn it off.
Open the lid.
Does the air inside it feel warm?
Is the water cool?
If it is too warm, it slow-cooks the stems... it means your water-pump is over-heating (common in EZ cloners!)
Use a 24-hour 15-minute increment timer ($10 @ Lowes) set it to turn off for 15 minutes every hour... this keeps the pump from over-heating the water.
Once all this is done/checked-- you need a cloning solution. The Sprayers often spray so hard they just wash-off the cloning gel- and that little bit of gel isn't enough in that amount of water to be effective as a "solution." Buy whatever solution is made by the same company as your gel-- or try the one by Clonex or Rootek... I do not suggest Olivia's in the sprayer type systems, tho I like the product, it is better for DWC or plug-cloning, as it can clog spray emitters.