Water Tank Level Monitoring System

[ExpatOilWorker]

I have this 36 m3 tank to capture rain water for domestic consumption. 

What is the best way to monitor the water level?

When full, the water level is 2.25 m, so the below 4-20 mA for a 0-5 m span would kind of do the job, but is there a way to capture the data to see seasonal variations in the water level.

Some sort of app or data acquisition system?

https://s.lazada.co.th/s.enY4R

 

https://s.lazada.co.th/s.eNz2a

 

[cjinchiangrai]

You are really overthinking the problem. Each morning you can type a new number into your spreadsheet. It can easily be automated with some simple software and a voltage tap from either the sensor or the PLC.

 

[VocalNeal]

Pick something that says water. Not fuel. Otherwise your 5m becomes 4.25m. OK in your case but it still needs to be calibrated, if it has any adjustment. Something more like 3m water would be simpler. 0-75%

Your data system will have to be powered 24/7 or have UPS back up. Your chosen display needs a repeater output to data collection system. 

 

Where you find a 4-20 (1-5v with resistor) input card and the actual date collection is not my area of expertise or interest. 

 

Using the cheap indicator and a CCTV camera you could monitor everyday from anywhere. But data would need to be input manually into a spread sheet.

 

An automated rain gauge could measure season rainfall but won't help with monitoring the water used from the tank only the input.

 

 

 

 

 

 

 

[SnowyWiez]

Also if the data aq system is near the rain fall tanks. Going need to put in probably a weatherized box. Cheap and get same source. 

How are you powering it?

What level of resolution do you need (float type sensors are cheap and could do one at various levels as optical need some calibration and more expensive typically) 

Then also ask how often data needs to collected and how your going to grab the data. 

Higher end ones can have wireless modules where you can login and download. Or cheaper you can connect to a usb or whatever port they come with.  

[ExpatOilWorker]

3 hours ago, SnowyWiez said:

Also if the data aq system is near the rain fall tanks. Going need to put in probably a weatherized box. Cheap and get same source. 

How are you powering it?

What level of resolution do you need (float type sensors are cheap and could do one at various levels as optical need some calibration and more expensive typically) 

Then also ask how often data needs to collected and how your going to grab the data. 

Higher end ones can have wireless modules where you can login and download. Or cheaper you can connect to a usb or whatever port they come with.  

The tank in a basement section of the house so power and protection from weather is no problem.

It would be nice to have a graph of the seasonal variation of the water level in the tank.

Something like the below, but it come at a cost. 750 NZ$.

 

[SnowyWiez]

5 hours ago, ExpatOilWorker said:

That be a nice one package. Are the three tanks tied in to each other / same size so only need 1 sensor array? 

If your a DIY and bored as hell like most of us during covid could be a fun project to get a simple data aq board, few float switches lol  

 

The tank in a basement section of the house so power and protection from weather is no problem.

It would be nice to have a graph of the seasonal variation of the water level in the tank.

Something like the below, but it come at a cost. 750 NZ$.

 

 

[ExpatOilWorker]

It is a fun DIY project and the level sensor is just one part.

I also plan to install UV disinfection,  so the tank will have a cool futuristic glow like below.

 

[Crossy]

On 7/30/2021 at 5:34 AM, ExpatOilWorker said:

It is a fun DIY project and the level sensor is just one part.

I also plan to install UV disinfection,  so the tank will have a cool futuristic glow like below.

 

Someone is going to ask where you keep your nuclear reactor ???? 

 

[KeeTua]

On 7/27/2021 at 8:26 PM, ExpatOilWorker said:

What is the best way to monitor the water level?

When full, the water level is 2.25 m, so the below 4-20 mA for a 0-5 m span would kind of do the job, but is there a way to capture the data to see seasonal variations in the water level.

A vertical clear tube on the outside of the tank with a ping pong ball or foam float to indicate water level. Use an IP camera of some sort to snap a few images daily. Update your spreadsheet from the readings in the images. One big advantage to this is anybody in your household can determine the water level visually from an image or by visiting the tank, no need for an app.

[FarangRimPing]

Just ordered this from Ali Express:

 

THB 1,326.24  41％ Off | Ultrasonic Water Tank Level Meter Temperature Sensor Low battery Liquid Depth Indicator Time Alarm Transmitter Measuring Tools

https://th.aliexpress.com/item/32965118880.html

 

[ExpatOilWorker]

46 minutes ago, FarangRimPing said:

Just ordered this from Ali Express:

 

THB 1,326.24  41％ Off | Ultrasonic Water Tank Level Meter Temperature Sensor Low battery Liquid Depth Indicator Time Alarm Transmitter Measuring Tools

https://th.aliexpress.com/item/32965118880.html

 

Did you see the review (2-14 minutes)?

 

 

[Muhendis]

Place load cells under each leg of the tank and feed result into computer. Size and shape of tank added to calculation to work out height also add information to compensate for impurities in water........????

[ExpatOilWorker]

3 hours ago, Muhendis said:

Place load cells under each leg of the tank and feed result into computer. Size and shape of tank added to calculation to work out height also add information to compensate for impurities in water........????

Not a bad idea, but it is a 36 m3 tank build into the structure of the house.

[FarangRimPing]

7 hours ago, ExpatOilWorker said:

Did you see the review (2-14 minutes)?

 

 

No, I didn't. Thank you. We'll see how it works in action.

[Muhendis]

4 hours ago, ExpatOilWorker said:

Not a bad idea, but it is a 36 m3 tank build into the structure of the house.

Aah.

A bit tricky then.

[Muhendis]

On 7/27/2021 at 8:26 PM, ExpatOilWorker said:

but is there a way to capture the data to see seasonal variations in the water level.

Google "PLC data logger" then take your pick.

[ExpatOilWorker]

46 minutes ago, Muhendis said:

Google "PLC data logger" then take your pick.

Thanks for the tip, this sound like the right solution.  Obviously you know data acquisition and electronics. Any chance you can suggest a model, that is available in Thailand on one of the online platforms, including AliExpress?

[Muhendis]

11 minutes ago, ExpatOilWorker said:

Thanks for the tip, this sound like the right solution.  Obviously you know data acquisition and electronics. Any chance you can suggest a model, that is available in Thailand on one of the online platforms, including AliExpress?

The last time I worked with these user friendly guys was many years ago but they are still current and the model I worked with was a Mitsubishi FX series. I would think you would need some peripherals (input conditioning, memory, display/wireless interface etc.) to go with the base unit but they aren't too expensive and the GUI makes them a doddle to set up. Lazada et.al. have them.

[ExpatOilWorker]

3 hours ago, Muhendis said:

The last time I worked with these user friendly guys was many years ago but they are still current and the model I worked with was a Mitsubishi FX series. I would think you would need some peripherals (input conditioning, memory, display/wireless interface etc.) to go with the base unit but they aren't too expensive and the GUI makes them a doddle to set up. Lazada et.al. have them.

Appreciate your support. Are we talking something similar to the below from AliExpress?

Can I then connect the 4-20 mA sensor direct to the PLC data logger and skip the original display box?

 

THB 2,971.00 | 4 channels paperless recorder chart recorder temperature data logger pressure humidity current voltage curve monitoring 4-20mA
https://a.aliexpress.com/_msV1gIB

 

Or this:

THB 3,631.22 | 1 2 3 4 5 6 Channels Paperless Recorder Temperature Chart Recorder PT100 K  J 4-20mA Datalogger Humidity Current Voltage Flow
https://a.aliexpress.com/_m0QPi4L

[Muhendis]

46 minutes ago, ExpatOilWorker said:

Appreciate your support. Are we talking something similar to the below from AliExpress?

Can I then connect the 4-20 mA sensor direct to the PLC data logger and skip the original display box?

 

THB 2,971.00 | 4 channels paperless recorder chart recorder temperature data logger pressure humidity current voltage curve monitoring 4-20mA
https://a.aliexpress.com/_msV1gIB

 

Or this:

THB 3,631.22 | 1 2 3 4 5 6 Channels Paperless Recorder Temperature Chart Recorder PT100 K  J 4-20mA Datalogger Humidity Current Voltage Flow
https://a.aliexpress.com/_m0QPi4L

Both of these instruments do what you want. They are both data loggers They both have recorded storage capacity. I don't think you would need a PLC if you used one of these but you would need to arrange a data dump into a pc to organize and view the records. This could be a manual task say once a month or something like that. The records may be in a suitable form for excel. How/if you can achieve that will demand IT skills which may be fine for you but would require a bit of trial and error for me. I suspect there may be some software to take RS485 data direct into excel format.

[ExpatOilWorker]

 

9 hours ago, Muhendis said:

Both of these instruments do what you want. They are both data loggers They both have recorded storage capacity. I don't think you would need a PLC if you used one of these but you would need to arrange a data dump into a pc to organize and view the records. This could be a manual task say once a month or something like that. The records may be in a suitable form for excel. How/if you can achieve that will demand IT skills which may be fine for you but would require a bit of trial and error for me. I suspect there may be some software to take RS485 data direct into excel format.

This one looks most fun, with the graph option: https://a.aliexpress.com/_m0QPi4L

I will give it a try.

Hopefully it is some sort of excel compatible data format. Worse case, I would have to make an excel macro that sort the data in a single column. 

Thanks for your help.

[MrJ2U]

On 7/30/2021 at 5:34 AM, ExpatOilWorker said:

It is a fun DIY project and the level sensor is just one part.

I also plan to install UV disinfection,  so the tank will have a cool futuristic glow like below.

 

What a great idea!

 

Where can I get one?

 

[Muhendis]

9 hours ago, ExpatOilWorker said:

 

This one looks most fun, with the graph option: https://a.aliexpress.com/_m0QPi4L

I will give it a try.

Hopefully it is some sort of excel compatible data format. Worse case, I would have to make an excel macro that sort the data in a single column. 

Thanks for your help.

Yes, that bit of kit looks good especially since it has a USB connection. Although that is mentioned as a power connection maybe it is also a data port. Printer port is probably useful too.

[ExpatOilWorker]

3 hours ago, Muhendis said:

Yes, that bit of kit looks good especially since it has a USB connection. Although that is mentioned as a power connection maybe it is also a data port. Printer port is probably useful too.

I decided on the 6 channel box, then I will also ties in 2 flow meters and probably a temperature sensor,  although I expect the temperature to be fairly constant throughout the year 

Our little project is coming together. Now we just need some rain. Tank is currently down to 65 cm and we are dropping 2 cm/day.

 

 

[Saanim]

On 8/5/2021 at 11:14 AM, ExpatOilWorker said:

Now we just need some rain.

If you have the rainwater inlet(s) directly in the tank, the water inside will be very dirty during the rainwater flow unless it settles few hours later.  Than only you can take quite a clean water some 10 cm above the bottom. You will see the mud after the season even if you provide for any protection of the gutters and their inlets into the tank. The fine dust - not only from the roads - but from the surrounding vegetation,  settles on the roof within a day even after heavy rain. 

 

How to flush out the black mud laying onto the bottom, good to think on properly before construction.  Sometimes you will have to dive in, a strong water spray is not enough, especially when no slope at the bottom and the drain outlet is not really at the lowest point. And sufficiently large (2"). 

 

And when the tank is underground? Then you need a good portable submersible pump that can take the mud. However, if not a deeper spot where the pump can suck from, how to suck the last 1 " of water? 

 

This experience I have made over years. Now, from these rain harvesting tanks I take the clean settled water into a smaller storage tank (filled in also by the city water when no rain) where from the automatic pump supplies the house and swimming pool.  And of course through a pressure vessel sand filter that can be backwashed regularly. You will be surprised after few months how long you will need to backwash until getting a clean discharge.

 

A timely addition of chlorine (the easy one, not the one for swimming pool with Cyanurs) is recommended into longer laying storage.   

 

[ExpatOilWorker]

34 minutes ago, Saanim said:

If you have the rainwater inlet(s) directly in the tank, the water inside will be very dirty during the rainwater flow unless it settles few hours later.  Than only you can take quite a clean water some 10 cm above the bottom. You will see the mud after the season even if you provide for any protection of the gutters and their inlets into the tank. The fine dust - not only from the roads - but from the surrounding vegetation,  settles on the roof within a day even after heavy rain. 

 

How to flush out the black mud laying onto the bottom, good to think on properly before construction.  Sometimes you will have to dive in, a strong water spray is not enough, especially when no slope at the bottom and the drain outlet is not really at the lowest point. And sufficiently large (2"). 

 

And when the tank is underground? Then you need a good portable submersible pump that can take the mud. However, if not a deeper spot where the pump can suck from, how to suck the last 1 " of water? 

 

This experience I have made over years. Now, from these rain harvesting tanks I take the clean settled water into a smaller storage tank (filled in also by the city water when no rain) where from the automatic pump supplies the house and swimming pool.  And of course through a pressure vessel sand filter that can be backwashed regularly. You will be surprised after few months how long you will need to backwash until getting a clean discharge.

 

A timely addition of chlorine (the easy one, not the one for swimming pool with Cyanurs) is recommended into longer laying storage.   

 

Thanks for your advise, you and me are on the same page.

I will have a 2 layer sock type filter on the ingress, the rain gutter, side of the tank. I have noticed gecko poop on the roof and we know where it is heading.

I will experiment with 200 and 400 mesh primary filter and see what works best.

 

Phase II, is to have a 1,000 l/hour solar circulation pump slowly rolling the tank through a filter and a UV sterilization tube. 

 

We will have Perrier crystal clean water.

 

[Muhendis]

8 minutes ago, ExpatOilWorker said:

Thanks for your advise, you and me are on the same page.

I will have a 2 layer sock type filter on the ingress, the rain gutter, side of the tank. I have noticed gecko poop on the roof and we know where it is heading.

I will experiment with 200 and 400 mesh primary filter and see what works best.

 

Phase II, is to have a 1,000 l/hour solar circulation pump slowly rolling the tank through a filter and a UV sterilization tube. 

 

We will have Perrier crystal clean water.

 

What people in the village near me do is to divert the first rain away from any storage vessel. This cleans all the loose crud off the roof. After that the water is much cleaner and quite collectable. Needless to say, they don't drink it.

[Saanim]

3 hours ago, ExpatOilWorker said:

Thanks for your advise, you and me are on the same page.

I will have a 2 layer sock type filter on the ingress, the rain gutter, side of the tank. I have noticed gecko poop on the roof and we know where it is heading.

I will experiment with 200 and 400 mesh primary filter and see what works best.

 

Phase II, is to have a 1,000 l/hour solar circulation pump slowly rolling the tank through a filter and a UV sterilization tube. 

 

We will have Perrier crystal clean water.

 

As I said, whatever filter you will organize you will get surprised by the settlement after some time.  And when the filter too thick, the water will go around.

 

And when the solar pump will transfer the water (because suddenly a nice sunshine after the rain) whilst the water not settled...  

 

Repeating what I said, even after a heavy rain the harvested water from the roof next day is not clean. 

 

If you buy a simple cheap pump 220 V you can re-pump the water as per your decision once in 1 -2 days, with a 10 minutes pumping you are served for few days. Do not rely too much on gadgets. 

[ExpatOilWorker]

21 hours ago, Saanim said:

As I said, whatever filter you will organize you will get surprised by the settlement after some time.  And when the filter too thick, the water will go around.

 

And when the solar pump will transfer the water (because suddenly a nice sunshine after the rain) whilst the water not settled...  

 

Repeating what I said, even after a heavy rain the harvested water from the roof next day is not clean. 

 

If you buy a simple cheap pump 220 V you can re-pump the water as per your decision once in 1 -2 days, with a 10 minutes pumping you are served for few days. Do not rely too much on gadgets. 

The water is already clean as it is, but it must have been years since the tank was properly cleaned.

Confined space entry needs a PTW (permit to work) in my industry, so I am waiting for a 250 m3/h blower before I will enter the tank and clean it out. Safety first!

The sock type filter never overflow and I will experiment with 200 and 400 mesh material, so nothing bigger than 0.07 mm enter the tank.

The UV recirculation system will have a separate filter.

Fun times.

 

[Wombo1]

It looks like your trying to replicate the demin water system from your work ????

 

next just add in an enraf system