# Forum Home Renovation Plumbing  Smelly rainwater tank!

## henlan77

Hi all,
My new house in southern NSW has an 8,000L rainwater tank located in the basement/garage. There is a first flush diverter (ball float-in-pipe style) and a mesh screen between the inlet and the tank. 
However we have been getting a lot of bugs and beetles coming off the roof and getting caught by the mesh. If I don't empty the mesh soon enough the incoming water washes over the bugs and the tank water gets smelly and putrid. 
My plumber calls them S#!% Beetles and says there is not much that can be done. 
The water is used only for the garden so it is not a health concern. However the water stinks and the smell floats through the house. 
Is there a product I can pour into the tank to kill any bacteria/algae or whatever it is and stop the smell? A disinfectant or antibacterial or something? There is a pump connected to the tank so I don't want anything corosive that would damage seals etc. Nor anything that could kill the garden! 
Thanks in advance.

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## Vernonv

Chlorine.

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## SilentButDeadly

As the Vernon says.......chlorine is ideal.  
Just use a floating tablet dispenser as you would in a pool....just remember to tie it off though to somewhere near the access hole otherwise it could get awful hard to reach!! 
Might also be worth considering a leaf diverter - it might divert a few beetles and bugs as well.

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## henlan77

Thanks guys.
My concern is that the chlorine could damage the pump. I once put chlorine (admittedly a large amount) into a garden pond and the pump lasted about 1 week! Do you think most domestic water pumps can handle a bit of chlorine?

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## Vernonv

You may want to talk to a pool chemical place about how much chlorine to use. 
When you think about it most pools pumps last many, many years ... so it's about getting the right balance.

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## Bloss

The amount of chlorine is very small for this purpose, but tanks getting smelly is very unusual so I'd be looking a bit harder for the cause (IMO not likely to be those beetles). A sloped leaf catcher and another fine mesh screen on the inlet would be a start as other have said - these do not have to be close to the tank. 
Smells are usually of bacterial origin - algae looks nasty, but doesn't usually emit smells until it dies and bacteria start to break it down. In any case algae needs light and this tank should have none. Smells shouldn't be occurring in a tank as described. There are algicides and tank dispensers for chlorination and salination too (and making sure you can retrieve it sounds self-evident, but not thinking about that happens often!) - even for potable use they are fine. 
Throughput is important too - tank water can only save your town water use if the tank is empty or near empty when it rains ie: you should use the tank water first then cut-over to town water so you get a newly filled tank next time it rains. Many systems have two take offs - one about 75-100mm or so from the bottom for draining and another that takes water at about 1/4 up so the tank. Tanks that have pumps controlled by floats inside the tanks often have the stop point at around 1/5 or so from the bottom. 
Still water is unhealthy water as oxygen depletes over time so a tank full of water sitting around for too long is not a good idea - that's why fish tanks have little air pumps to create turbulence and allow the water to absorb oxygen. 
Having cleaned a few too many (more than one) tanks in my time I tend to be fastidious about them - a tank for potable water should get an annual drain and clean. That is not always possible and with first flush devices, good mesh filters coarse and fine (to stop mozzies) and concrete or polythene tanks (or linings) once every two years is probably OK for most now. In the country where tanks are the sole potable supply that's another reason why there were always multiple tanks - timing was still pretty important as you didn't want to be stuck with a clean, but empty, tank for too long!  :2thumbsup:  
You say it is your new house, but if it is just new to you, but the tank has been in for a while a complete drain and clean might be the go since you are using it for garden only - as well as the review of the various filtering devices before the inlet.  :2thumbsup:

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## henlan77

Thanks for the info Bloss.
It is a new house, new tank, new roof, new downpipes (6 months old).
It is a black poly tank located in a cool, dark basement.
The S#%$ Beetles and collection of bugs in the mesh screen certainly does smell when I clean them out - a similar smell to the water. 
The only other thing I can think of is that the PVC inlet plumbing goes underground before coming back up and into the tank. I think this is called a flooded or submerged system (forgot the plumbing terminology). So a section of pipe about 10m long lies underground and full of water permanently. Perhaps there is a buildup of bugs, leaves or worse in this section of pipe. 
Hmmm, now how do I clean that out :Eek:

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## Vernonv

> I think this is called a flooded or submerged system (forgot the plumbing terminology).

   It's called a wet system.  
If you are lucky, whoever installed the system also put in a drain point (i.e. a screw cap on the pipe at the lowest point). This will make draining it easy. If there is no drain point then I think you're stuck. 
Having said that however, I have found that the wet systems (we have two major ones at our place) don't normally cause issue with bad water smells or any other issues for that matter.

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## Bloss

Seems as though you do need some extra filtering to allow bugs etc to roll off rather than sit for any time and rot into that pipe. Maybe one of these: http://www.watertankfilters.com.au/ although they can need cleaning often. 
Odd though - on a new install should be an issue for the plumber/installer to fix. I'd be getting them back in as that is most definitely not normal and the design should stop that from happening - whatever he says is the cause. The issue is not that bugs get in it is that the tank installation is faulty as it allows build up of dirty water - and that is the designer/ installer's problem to solve. They might be OK to ask you to pay for parts, but labour should be at no cost - but to get it fixed I wouldn't be arguing unless it seemed unreasonable. The looped down and up design is common enough - the water sitting in the should be clean though. 
Have a look at the manufacturers web site and installation instructions and confirm that it is to spec. I have seen that design for potable water in places where it rains very infrequently and there is no water 'smell' - you need to get them back in.  :2thumbsup:

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## henlan77

Thanks Bloss and Vernonv. Top advice :2thumbsup:

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## Border boy

Hi Henlan77,
I put a 10000 l tank in a year ago - big first flush diverter & leaf eaters like SBD's pic. I quickly realised that I had to clean the filter of the first flush diverter after pretty much every rain event (few & far between here) as well as the leaf guards, Maybe the beetles & stuff are sitting in a clogged diverter & contaminating your tank??
We only use the tank for the garden but so far the water is good enough to drink.

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## elkangorito

Don't use chemicals...especially chlorine.
Instead, install a blower to aerate the water for a few hours per day. This will stimulate the growth of aerobic bacteria, which will greatly reduce the smell.

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## Bloss

> Don't use chemicals...especially chlorine.
> Instead, install a blower to aerate the water for a few hours per day. This will stimulate the growth of aerobic bacteria, which will greatly reduce the smell.

  Neither chemicals or aerators should be needed if the tank and inlets are properly designed and installed. But .  .  .  there are drinking water tank aerators commercially available. And chlorinators for tank are safe and treat in much the same way as tap water - with little impact on anything at all - including the notorious 'chlorine smell' which occurs only in improperly functioning chlorinating systems (as too many local council run systems are - often very old and in poor condition).

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## woodbe

Thanks for the reminder. It's just about time to get the water in the tank tested and change the filters before switching over to rainwater once the worst of the fire season is over. 
I have a good link for well priced replacement water filter cartridges if anyone is interested. 
woodbe.

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## Vernonv

> I have a good link for well priced replacement water filter cartridges if anyone is interested.

   Are these the approx 200 x 50 diameter cylindrical ones? What's your source? 
I normally pay about $6 for a 5 micron filter from the local pump and irrigation mob. The last time they needed changing (every 3 months of so - whole house system) I got some from the local Swan Plumbing, as I was already in there for something else. The two filters came to around $45 ...  :Shock:  ... needless to say I declined the purchase.

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## woodbe

> Are these the approx 200 x 50 diameter cylindrical ones? What's your source? 
> I normally pay about $6 for a 5 micron filter from the local pump and irrigation mob. The last time they needed changing (every 3 months of so - whole house system) I got some from the local Swan Plumbing, as I was already in there for something else. The two filters came to around $45 ...  ... needless to say I declined the purchase.

  That's an unusual size? You're right, I could buy 3 of my large filters for that... 
No, mine uses the 20" x 4.5" 508mm x 114mm (it's an industry standard US Size) Pleated paper for the 5um filter. These have masses of filter area, so they run for considerably longer before clogging up. We also run a carbon filter with replaceable carbon. Depends on your water quality and volume used, but we find they last around a year between changes. At a year, we change them anyway. 
Always beware of people flogging filter systems offering non-standard sizes - they lock you into buying their own custom cartridges at outrageous markups, and often their gear is overpriced as well. We got ripped off for ours, but luckily it was standard sized gear. We save over 80% of the replacement costs by buying from Peter at PSI Filters in Tasmania. (good guy, no relation, just happy customer) 
woodbe.

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## Bloss

I hope you blokes are filtering tank or bore water - waste of money filtering town water IMO . . . (even in Adelaide although it sure has water you can taste!)  :Smilie:

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## woodbe

> I hope you blokes are filtering tank or bore water - waste of money filtering town water IMO . . . (even in Adelaide although it sure has water you can taste!)

  Bloss, you clearly have your tastebuds in the wrong place  :Biggrin:  
We use it for both Adelaide Tap water and our own tank water.(we switch over to tank late summer) 
Where we are, it's worth it for the improved taste of townwater. In any case, it saves all the grunge coming down the line from stuffing up all the tap seals. You should see the junk that it stops! 
woodbe.

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## Bloss

> Bloss, you clearly have your tastebuds in the wrong place 
> You should see the junk that it stops!
> woodbe.

  On the former many say I have no taste at all  :Smilie:  , as to the latter that's what the alimentary canal is for . . . getting rid of junk that is . . . :Biggrin:

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## Vernonv

The cartridges I use are a very common variety (they are actually 10 inch not 200mm) - here is an example http://shop.aces.edu.au/water-filter...es/cat_20.html 
We use 2 x 5 micron cartridges in parallel for whole house filtering. We don't have any town water, so only run tank water.

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## woodbe

Ah, that's better - standard size. 
You run them parallel. Why is that? 
If I were to just do the sediment thing, I'd probably run a 10 and a 5 in series. Probably find that they both last longer that way. 
woodbe.

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## Vernonv

> You run them parallel. Why is that? 
> If I were to just do the sediment thing, I'd probably run a 10 and a 5 in series. Probably find that they both last longer that way.

  Better flow rate. I get twice the flow rate as I would if I only had a single 5 (remember this supplies water for the whole house). I remember doing the sums at the time (7 or 8 years ago) and a single 5 would have been be just given us an acceptable flow rate. Two in parallel gives us plenty of capacity to spare. 
I'm quite happy with 3 months between change overs (we often stretch it to 4 months). Only costs about $12 a go ... pretty cheap really.

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## woodbe

Fair enough.  :2thumbsup:  
We have never had a problem with our flow rate on mains or tank through the admittedly larger filters. Are you using pleated paper filters? From what I've read, the pleats give more surface area for the same size filter, and less pressure drop across the filter. 
woodbe.

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## Vernonv

Nah, we use the poly spun types. The pleated filters do offer slightly better flow and they can be cleaned and reused, but cost substantially more than the spun cartridges.

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## GraemeCook

> Thanks guys.
> My concern is that the chlorine could damage the pump. I once put chlorine (admittedly a large amount) into a garden pond and the pump lasted about 1 week! Do you think most domestic water pumps can handle a bit of chlorine?

  
I'd also be concerned about putting chlorine on the garden - its a reasonable herbicide. 
Cheers 
Graeme

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## Bloss

> I'd also be concerned about putting chlorine on the garden - its a reasonable herbicide.
> Cheers
> Graeme

  The chlorine levels we are talking about for this purpose are the same as for tap water (about 2-3 parts per million - even a pool or spa is usually at around 5-8ppm) - no evidence that I am aware of that suggest any  problem for plants at those levels . . .

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## totoblue

Could also be a problem with possum poop.  If that is washed into a filter, it is big enough not to go through but it will sit there being washed by water and broken down to dust which will go through most filters. 
If you have trees overhanging your roof, and possums in the area, a large part of the stuff caught in inlet filters will be possum poop.  Same with birds I suppose. 
We only have inlet filters on our tanks.  A lot of possums here.  One of the tanks doesn't have room for a leaf eater or similar rain head (not enough vertical height) and with the small rain events we normally get here in Melbourne a first flush diverter would divert most of the rain.  I (try to) empty the inlet filter after every rainfall.  It's only for the garden so a bit of pooh is ok. 
I've noticed the water in the tank is quite stinky at the moment as we haven't had any inflow for months and the water level is getting very low plus being slowly cooked in the heat we have had.

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## Bloss

First flush devices, angled coarse screens, fine mesh filters and HEPA filters for drinking water should mean this is never an issue.  :2thumbsup:  In any case this is water for the garden - but the tank location means any smell (and there should be none anyway - see above) is a nuisance.

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## totoblue

> Maybe one of these: http://www.watertankfilters.com.au/ although they can need cleaning often.

  These look like they are made from polyester wadding which is cheaply available at shops like Spotlight.  My wife bought some for me, and I just cut a circle of it and stuck it on top of the inlet filter.  We'll see how it goes when we actually get some rain.

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## GraemeCook

> The chlorine levels we are talking about for this purpose are the same as for tap water (about 2-3 parts per million - even a pool or spa is usually at around 5-8ppm) - no evidence that I am aware of that suggest any  problem for plants at those levels . . .

  
No worries, Bloss.   I presumed we were talking about a stronger dose of chlorine to kill the bugs that are causing the smells, rather than a 'maintenance' level inoculation. 
Cheers 
Graeme

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## ann00

i had a similar problem with my tank a while ago and didn't want to treat it with chemicals. i ended up coming across a 100% organic product in bunnings called Biowish Pond & Tank Conditioner. it worked really well and i haven't had a problem with odor since.

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