Backyard Aquaponics
A place to discuss aquaponics

Help respectfully requested.

I find it difficult to locate answers to these questions:

1. What options and equipment exist for regular water quality testing?
2. Is measuring dissolved oxygen useful?
3. Where can I get simple litmus paper to test pH?
4. What methods are used to adjust/correct results?
5. What does occasional frothing of the water indicate?

Gratefully,
Adrian

Since the Aussies are mostly asleep, I'll try tackling a few of these

1, winging it, indicator papers, titration test (tubes & drops), electronic meters; this is in order from least expensive and least accurate to most expensive and most accurate
2, can be. Most people seem to do OK if they have lots of aeration in their return streams via autosiphon or something similar
3, fish store
4, pH tends to come down as a system gets older. You can counteract this by adding sources of friendly alkali materials like crushed egg shells or sea shell grit
5, no idea

3. wouldn't bother, you need something relatively accurate

5. possibly high levels of dissolved organics / proteins?

1. There are many options for water quality testing. I think most people on the forum are using something like a master test kit (for aquariums) has test tubes and bottles of drops along with instruction cards, that tests for pH (two different ranges), Ammonia, Nitrite, and Nitrate. Seems reasonably accurate within the ranges it's meant for and provides a fair number of tests for the price. There are all sorts of other test kits for most other paramiters but the above listed ones are what most people are doing (would you jump off a bridge after us?) There are also electronic meters you can get, they tend to cost more and be ware of hidden costs of probe replacement, cleaning solutions, storage solutions, calibration solutions etc. I have a electric pH tester that seems to have gone belly up and only reads 7 now too and no amount of soaking in the special solution and trying to re-calibrate seems to do anything. It was cheap so I guess you get what you pay for.

2. I don't know, I got a couple little kids science kits that can do a couple DO tests to play with but otherwise I'm not set up to test that.

3. You can probably get those at any hydroponics store and probably off the internet but they aren't very accurate.
I've gotten and used the simple cheap pH test strips, they only seem accurate as extremes are approached anywhere between 5.5 and 8.5, they always seem to read 7.

4. pH can be adjusted many ways but remember to always do it slowly and carefully especially if you have fish or plants in the system as they don't like pH bouncing. Egg shells, shell grit as noted before are a pretty good way to help buffer up as they are not likely to cause a major overshoot in pH. Once a system has cycled, I've come to expect that you are unlikely to need much to bring pH down (My water comes out of the well with a pH around 7 which rises to 8 as the CO2 escapes with aeration but after only a few weeks of cycling my system will bring that down to 7 again on it's own.) But if you need to bring it down something like lemmon juice or vinegar might help but only temporarily, be very careful with it. I Never did anything to my AP system to bring the pH down and cycling got going fine at the higher pH of 8.

Correcting other results? Like what? Too much Ammonia, Nitrate, or Nitrite and you have fish in the system usually calls for some partial water changes untill things are under control.

Not enough DO, add an air stone and air pump. (this can also help your fish some in the event of high ammonia readings etc.)

5. What Steve said.

1.The fish are a pretty good indicator of water quality.
Test kits are very useful for keeping tabs on new tanks/systems but once things have settled down, most won`t see the light of day much after that..so don`t go spending a small fortune buying every kind

2. see above.

3. A ph meter is probably a worthwhile investment, much better than ph test strips, mine is 2 years old and still going strong.. cost £30.

4. Probably depends on your water to some extent, we have very hard water here and the ph is difficult to shift for any length of time.. so it just sits at around 6.3

5. agree with Steve

3. PH meters MUST be tested periodically against known buffer solutions to prove accuracy. The can drift horrendously out of calibration with general use. also follow the "storage" instructions to the letter.

Thats why i like drops so much.

I didn't think I'd like the drops but after fighting with test strips and a meter that wouldn't work right, the drops suddenly seem so much easier/cheaper.

drops rock, and after doing the two part ammonia and nitrate tests, the one part PH (and nitrite) are a welcome test

pH meters and probe will always give better results than any other. I use gel filled probes (TPS) and they are spot on. Meters don't usually cause problems. calibrating between 7 and 4 should only be periodical. The trick is to make sure that the buffer temp and temp your water is the same unles you have a built in temp compensation (expensive) .

Interestingly enough, pH vs temp is not that important unless your above 40 and less than 10 except at high pH (>9) typically you will see less than 0.1 pH difference

I use gel filled probes too with bnc connectors on 10ft leads. I check the calibration monthly but other than that they stay in the tanks 24/7.
I`ve found them very reliable, just flick the switch on the display and theres the ph reading. I really wouldn`t trust any from ebay though

http://www.monitors-direct.co.uk/Produc ... uctID=1159

tamo 42, steve, steve, steve, TCLynx, Hex, Baz n Al
Thank you so much for your advice. The collective wisdom available is breathtaking.

Adrian

I have a problem with my bore water being alkaline. The fish pond and GB receive over spray from the reticulation system and the pH climbs past 8.4 regularly.
I have found lemons and vinegar are very weak acids and do not have much effect on the pH, unless a lot is used.
I now use diluted pool acid (HCl) to control the rising pH.

Falling pH is easy to control using egg shells, shell grit, or other calcium based solids. These substances buffer the pH effectively for falling pH. Is there a substance which is able to buffer against rising pH?.
Peat is acidic. Would that be an acceptable organic remedy? Would it be effective?

Should AP be granted organic certification, what other options are there to control rising pH which would be acceptable within the organic certification.

Regards,
Tony

Coco peat, coco coir fibre used as a growbed medium often has a pH of 5.7 - 6.5.....

Will discolour the water and has a high water retentiveness....

Needs to be setup as a drip type system or on a timer with extensive "off" periods so that the coir/peat drys....

Often only "flooded" two - three times daily in a full flood and drain situation or even with drippers.

The water retentiveness and the way the coco fibres pack down/together also compounds possible root rot problems by (IMHO) also restricting the available oxygen to the plant oxygenating roots....

I see in another thread the system utilising "stacka" pots uses a 10 - 20% perlite and coir mix.... presumably to improve the oxygenation of the media.....

Something I intend to trail.... most others have gone away from straight coco-coir media because of the reasons mentioned.... and because most people are battling the opposite pH tendancies...

If your using HCI to drop the ph, you should definitely check your KH (carbonate hardness) levels beforehand.
With a low KH, adding HCI will likely cause the ph to crash pretty rapidly.

A possible alternative "new" product could be applicable in your situation Tony..... "Maidenwell".... pH 5.7.... becoming very prevalent in the hydroponics industry....

Has the benifits of the pH buffering as well as good drainage... and some trace element compounds as well.