Thank you for your comment.

All I can say is that currently, the X10 is the only device that measures salinity, but there's a good chance more HYDROS devices will be available in the future.

For normal Alk testing, you would use 3 of the 4 dosers. So there would be one spare doser to use at your leisure.

That is correct. If you want to monitor salinity you will need the salinity kit with the dual calibration solutions. If you are testing alkalinity remotely using the iV then yes you will need another pH probe and controller with an available probe port as the X10 only has one. If you are not doing alk testing then the pH would be in the sump with constant monitoring.

It really depends on what the aquarium carbonate hardness kH is at. If it higher at 9-10dkh you will use up more reagent per test and run out of reagent faster that one who has a lower system dkh. I tend to get a little over one month with a 1000ml and testing every 4 hours with a system alkalinity at around 9-9.5dkh.

Yes, tubing length is critical. You can go as short as you want but there are restrictions to the length of tubing which can be located here for more details: www.coralvuehydros.com/product-support/hydros-control/add-iv-tester/

Never mind. I went ahead and got the X10.

The salinity probe is only required if you want to test for salinity otherwise it is not required for alkalinity testing. I would suggest submitting a support ticket at support.coralvue.com to assist you in getting the stirrer working.

I am sorry to hear of your disappointment but the included 25mL beaker is for common calibration of the X10 dosing pumps like for the additions of two part or microelements. A larger Beaker was not included to drastically keep the price of the product down since it is not required unless doing Alkalinity testing which would require additional devices like the iV. For calibration practices for Alkalinity testing with the iV require a larger 100ml+ beaker or better yet a scale for precise measurement.