Thursday, 24 August 2023

Taking the plunge


Every year as summer digs its heels in and the temperature sits in the high 30's (°C) day after day with barely a cloud to be seen, we fantasize about the relief that having a pool would bring us. As it is currently, the best way of coping is to sit indoors with the shutters closed and artificial light on from when the sun hits us mid-morning until the sun finally drops below the hills opposite, an hour before official sunset. 

Last year (2022) the summer here was BRUTAL in central Italy. We had three months without a single drop of rain, quite high humidity and temps approaching 40°C for the entire time. It was an ordeal that impacts my depression. On top of this I am a self confessed collapsenik and follow avidly the current unravelling of our current civilisation and the ongoing derangement of the climate. As such I've been reading about the increasing danger of wet bulb temperatures as the climate worsens and throw into the mix the return of El Nino this year it made me seriously consider finding some way of cooling down at home without any further delay.

One of the main obstacles to us turning this idea into a reality has been the land we have around us. Italy is 41% hillside, 23% plains and the rest mountain. We occupy a tiny bit of the 41% and as such there is very little flat land here other than a small lawn in fron of the house, which is practically our dog's. Neither is it very big. 

I forget now what series of thoughts lead to the lightbulb moment but I was soon searching the internet for 'IBC pools' as a space saving alternative.

For the uninitiated, IBCs or 'intermediate bulk containers' are plastic containers inside a metal cage mounted on a pallet and are roughly a metre cubed in size and can hold 1000 litres of liquid and can be stacked for transport. Other sizes are available but these are the most common. Note that they come on three types of pallet. Wood, Plastic or metal. I strongly recommend either of the latter as in the picture below as the wood ones tend to rot after 3-4 years.
Cisterna IBC 1000 Litri in plastica, rigenerata con otre NUOVA, coperchio 150 mm, valvola di scarico 2", pallet in metallo, colore neutro, Tipologia: Otre Nuova e Gabbia Rigenerata, Capacità: 1000 Lt, Tipo Pallet: Metallo, Ø Coperchio (mm): 150, Omologazione ADR: NO, Colore: Neutro vendita, produzione, prezzi e offerte

We've already acquired more than 20 of these, used so far as growing containers in the garden having had the tops cut off and for harvesting rainwater from the house roof. As such I already knew of two suppliers selling them second-hand for very little money, around €30 each.

IBC raised bed
However (WARNING) you can't be sure what was sitting in them before you get hold of them. It could have been an innocuous food product or something incredibly caustic. While I have carefully pressure washed every container we've previosuly bought I wanted to be doubly sure that if  we were going to spend hours sitting in one filled with water there was no danger. After some searching I found suppliers of new IBCs but then also stumbled across a company nearby selling second hand cages with brand new food grade plastic containers inserted for half the price of a new unit. We paid €130 per IBC. 

We decided the site them at the north side of the house so that they would be mostly shaded during the day so as not to warm the water too much. It was also a small dead space between the rainwater harvesting IBCs and the fish pond. Seemed ideal! We had space for three IBCs so we bought three of them.

Having already found a few posts online of people making their own plunge pools I had a vague plan of how to proceed but the most helpful was this one on Instructables, although this plan included a heating element for using during colder months, not something we wanted.
We prepared the tanks by marking a level line around the cage and plastic tanks. Removed the plastic containers, cut the cages with a grinder and the plastic tanks with a jigsaw.

So with the tricky items sourced it's time to consider the rest of the bits and pieces and for that you need to consider water hygiene. 
With a small paddling pool you can simply dispose of the water and refill regularly. But with anything of a considerable size that amounts to a lot of water wasted. Given that when cut down to size we would use around 750 litres in each tank (total 2250 litres) then we needed to consider maintaining the water for the entire season.

There are two weapons in our armoury here: Chlorine and Filtered pumps.

Chlorine is excellent at keeping pathogens at bay and the water safe for sitting in but it's not without inherent issues that need monitoring. It will gradually reduce the PH of the water and soon it will become too acidic if not kept in check. So if using chlorine you need a means of testing the PH. Whether a digital tester or some simple strips that work like litmus paper.

With that in hand you need a way of amending the PH. Given that chlorine reduces it we have found we only needed to increase it this year, which we did by adding Bicarbonate of soda a tablespoon per day and re-testing until it sat in the sweet spot between 6-8PH. You can buy crystals for this exact purpose that I suspect would be a quicker solution. Equally you can buy crytals to lower the PH. I guess if you over dose one way you can counter it with the latter.

So, now we have chlorine in the water using floaters (pictured below) and slow release chlorine tablets inside them which last around one week.

Next you should consider a pump and filter combination. If chlorine left sitting in 'still' water it can quickly form Hyrdochloric acid. Even with my pathetic level of Chemistry knowledge I understand this is far from ideal for sitting in.

The way you combat this is to have a pump circulating the water keeping it moving, it stops the free chlorine bonding with water to form the aforementioned acid.

There are many types of pumps, some with and some without filters. If they have filters either they are sand or cartridge. Also pumps are rated at cycling a certain amount of water per hour.

We chose a pump that could pump a little more per hour than we had in total in the tanks and with a sand filter as these are low maintenance and the sand apparently lasts seven years before becoming less effective and needing replacing.

Not having too large a pump is important as this negatively impacts electricity consumption.

Once you have your 'pool' and pump/filter you need to connect them.

This is somewhat easier if you only have one 'pool' or IBC but not much more difficult with two or three.

Each pool needs an inlet and and outlet and for these you can find the 'jets' available online as you can with all the fittings needed. It seems here in europe there are two principle manufacturers, Intec and Bestway and from my experience their parts seem interchangeable.
NOTE: at this stage of planning you need to make sure that the pump, jets, taps and tube all have the same diameter. We used 38mm but 34mm would work fine in this setup.

You will need to cut a hole of the appropriate size into the plastic containers to accept these jets and make sure they sit in a position where there are no cage bars. So with the plastic containers inside their cages take a rubber washer from one of the jets and mark the holes by drawing around the inside of the washer while holding it against the plastic container. I installed the inlet jet higher up the wall and the outlet a little lower. This seems to be the standard with purchased pools and i guess and floating matter that needs filtering gradully sinks so this makes sense.

With the holes marker you can cut them either with a jigsaw, holesaw or with a steady hand a stanley knife works by pushing the blade through the plastic. I did the latter but be careful about mistakes, they would be tricky to remedy.

With the jets installed, you can connect the pump using the correct sizee tubing (either 34mm or 38mm) directly to the rear of these jets or you can add a tap so that you can close the pools off from the pump for any maintenance without draining the pools down, we did this and have already been thankful we did. I recommend the type of tubing below that has a cut point every metre that leaves you a collar either side of the cut to fit a jubliee clip.

If you have just one IBC you're ready to go. If not then you need to connect them in series using T pieces of the correct diameter.

If you have two IBCs then you will need two T pieces, for every IBC in addition you need two more T pieces. Having three IBCs we needed four T pieces.


38mm T connectors with jubilee clips

With the pools in place and LEVEL and the pump connected and filter filled with sand we filled everything with water, primed the pump (as per instruction booklet), opened the taps and switched on the pump.

After fixing a couple of leaky joints, it was ready for use and what a relief it's been this summer. We put in a couple of robust plastic stools so that you can comfortably sit inside with water up to chest height. You can see from the photo below that it's possible to drop in from the deck onto the stools. Depends how agile one is of course and this setup is purely because the deck is on top of the adjacent rainwater catchment tanks.

Next year I will most likely fit a ladder such as this to allow easy access into one of the pools for any visitors unable to clamber in and out without one. This will fix to the deck and descend into an IBC nicely.
If you are installing the IBC in a more freestanding setting the an even cheaper option for easy access could be standard pool ladder such as this below.


The water has ranged from 20-27°C this summer, entirely weather dependent and seems the night time temps are the largest factor. Even at the high end it's still very much cooling given that normal body temperature is 36-37°C. At 20°C it takes a little more commitment to sit into (a large pool you can simply jump in, these you need to sit down which is a whole other thing) but the benefits of cold water immersion are now becoming well documented so I'm embracing my inner Wim Hoff. Although he'd laugh at the 'warmth' of these pools, he prefers ice in his.
Fever - What you need to know - Rossmax | Your total ...

Once this season is over I'll leave the water to stand for three days or more to allow the Chlorine to gas off leaving the water safe for watering plants or storing for next spring in other IBCs that we will have below in the garden. I'll cover them over for winter and winterise the pump before freezing temps arrive. When spring arrives i'll give them a thorough clean and refill.

So what has this project cost?

The IBC tanks were €130 each
The pump €180
Pump grade sand €25
The jets (one pair) €25
The taps for the jets (one pair) €50
The T pieces (one pair) €12
The tubing €25
TOTAL €435 for one pool, each extra pool adds around €180

I must add that these costs excluded a little concrete so that i could make 8 level pads for the IBCs to sit on and the decking on the photo from you descend. Next year i'll probably clad the in reclaimed pallet wood and fix boards around the top edges as per the instructables article above.
SO...Worth it? Unequivocally. Why? Well, in the coming years these little pools could literally be a lifesaver as the climate deranges further. Deaths from heat in the exceed deaths from shootings (trying to remember where I read this, will update blog when I've found it), and there are around two mass shootings per day on average in the U.S. but i'm digressing slightly.
As I've already said at the top of the post. Prior to this year, summers were a case of putting the house into complete darkness during the day and sitting indoors. When this scenario is three months long it makes the summer a season to dread. This year however these pools have changed that. We still need to put the house into darkness of course, but we need not fear going outside and getting hot. We can consider doing some small activities knowing we can instantly cool down. Activites that we would otherwise have avoided as we had no convenient way of cooling quickly. The summer has just become less dreadful. Sitting in the pools with a book, enjoyable even. 

Any questions of clarifications then comment below please and i'll aim to improve the post.