Topic: Problem for use the Vantage Pro 2 Rain Gauge to calculate Ml/cup

[gastech]

Hi All

I use the Vantage Pro 2 rain gauge to calculate how many milliliters I can get from external water falling in the cup. I used a seringue to set to each cup = 4Ml. Manually if i use my seringue with 4Ml I can see that each cup fall when reached 4Ml, that's good. Take a note, at this time to top cover (cone) is not installed.

My problem is, when I pour 100Ml in the cone, I hope to have 25 cups but in fact I have only 19-20 cups, no more. I have an offset of 20Ml and in my use case, it's very big.

Anybody can help me to figure out my problem because now I feel alone and I have not idea what's wrong.

Thanks for you help
Gastech

[johnd]

My problem is, when I pour 100Ml in the cone, I hope to have 25 cups but in fact I have only 19-20 cups, no more.

Do you literally 'pour' or do you drip the 100ml in reasonably slowly?

[gastech]

My problem is, when I pour 100Ml in the cone, I hope to have 25 cups but in fact I have only 19-20 cups, no more.

Do you literally 'pour' or do you drip the 100ml in reasonably slowly?

If I take the time to drip 100ml, yes I can get be close of 25 cups or +/- 3 cups but my use case I use it to calculate the Ml from drip nozzle rated 2Ml/hour. I have an irrigation every 15 minutes during 5 minutes long.

[Old Tele man]

Normal "rain" fall consists of "drops" not a continuous "stream" as when poured and some small amount of water will always 'cling' to the cone surface area.

[gastech]

I understand what you said about rain and drop vs stream water but it's possible to make a workaround to be able to get the correct number of cups ? For you information, a normal irrigation period it's between 75ml to 125ml, not big. Do you think, I can put water in a old bottle of water and drill a small hole on the bottle cap to let evacuate more slowly the water into the rain collector hole ? I'll put the small nozzle of the drop inside the bottle, the water will drain by the cap bottle and fall directly in the rain collector.

[johnd]

Do you think, I can put water in a old bottle of water and drill a small hole on the bottle cap to let evacuate more slowly the water into the rain collector hole ?

Yes, that's the standard way of doing a gauge calibration.

[SoMDWx]

See no issue here.... You have just learned that tipping cups are not precise..... All you can do is keep the collecting cups free of dirt/debris......