DO NOT USE STRAIGHT RO WATER!!

Hi Drew. I do 50% water changes, use 25% straight RO, and the other 25% tap water and use Aqua Plus water conditioner with the tap. I do not mix my RO and tap in the holding tank, but others may. I too was surprised with the pH and TDS, but my fish seem to still love it....

My water then reads as follows:
TDS (straight from the tap) = 289
TDS (in the fish tank mixed with RO) = 186
TDS (RO holding tank) = 12

pH (straight from the tap) = 7.8
pH (in the fish tank mixed with RO) = 7.2
pH (RO holding tank) = 6.2

I am by no menas a water expert, and do not understand it myself, as you can see from starting this thread. All I do know, is that my fish like it better since I have been adding conditioned tap water!!! :P

Weezy

[wildthing]

Personal Peeve......

I have been very troubled recently by some people (in the the buisness less than a year but) recommending to keep Discus in straight r/o water, some using sea salt to 'add back'.
This is very inappropriate.
Sea salt ( nor any NaCl type salt) does not contain the correct minerals to reconstitute r/o . Straight r/o ( if your unit is working right) will produce water with no minerals at all, which will soon enough lead to HitH from mineral deficiency & other stress related body dysfunctions, not to mention that the water is not buffered & will pH crash ( as described above).
While the Amazon is very pure water with few minerals in it it is important to know which ones are present & replace them. There are also many dissolved organics which don;t show up on meter tests.

R/O MUST be reconstituted ( minerals added back, either by adding mineral supplements or tap water) to prevent these problems & IMO anyone saying different is lacking long term experience & giving dangerous advice.
DW

[SnowCichlid]

Would this apply to tanks that get well water ... I do not live in a big city and therefore my source of water is chlorine and chemical free ... the only thing that needs to be treated occasionally is the pH level tha comes from it

[Carol_Roberts]

Hi Snowcichlid:
I'm not sure I understand your question. . . are you asking about using your well water as is or whether you should use RO water?

[Steve_Warner]

Hi all,
Interesting thread here............I hope DW reads this again and elaborates on his belief that sea salts or any salts are dangerous to suggest. I'm very curious to know why he says this and am eager to know his thoughts(Chloride ions, maybe?). Many people hit the nail on the head by stating that R/O must be reconstituted before being added to a tank, 'cause this could lead to all sorts of problems, such as pH crashes, HITH, etc. One must understand the full cycle of water/chemical reactions and it's buffering capacity to get an idea of what is needed to keep relative stability in a tank. When a water body is low or devoid of buffers to prevent the acids from overwhelming the system, the water is in a danger zone in regards to pH crashes. Think of it as a sheer cliff and the buffers are the stoppers from going over that cliff. The more acids produced/added to use up the buffers, the closer to the edge of the cliff the water gets. (This is why it is very dangerous to use inorganic acids to lower pH by anyone but the most experienced aquarists who understand chemistry to a certain extent). Once a water body is exhausted of it's buffering capacity, the acids overwhelm the system EXTREMELY quickly!......thus a pH crash! There is a mechanism in nature to counteract this natural occurrance(acid production) called Denitrification, but it can only do so much to prevent a crash.


Steve

[Greg]

David, What do you add to your RO water to bring back up the mineral content?

[Carol_Roberts]

You can use a product like RO right or you can make your own. The receipe is:
1 gram Magnesium Sulfate (Epsom Salt),
1 gram Calcium Chloride (Sea Salt)
3 grams Calcium Sulfate (Gypsom)

[vendetta]

What's the reason of the pH crashing when use RO water?.. is it the lack of minerals?.. I'm starting with my firsts RO filter and I noted that pH grow from 6.5 to 7.5 slowly if I don't do water changes.

Regards.

[Second Hand Pat]

Low KH can led to a ph crash. KH is what buffers the ph.

[tolga]

Hi, what about wild heckels? I've been told to use straight ro which gives me water with 46 micro Siemens so there appears to be some minerals left in the product water. I've been using this straight on all my heckels. My tank is on a constant drip system. I have a bag of crushed shells which keeps the water around 1 KH. My Ph hasn't dropped to less than 6.4 in the last six months. I have been experimenting with seachem discus trace and I'm in the process of setting up a dosing pump to add the discus trace on a continuous basis. I'll be interested to know if there are any views on this. I'm not suggesting this is the best way but it has been pretty straightforward for me from day one and my juveniles have been growing in this water although the skittishness has been an issue from time to time but I'm not sure if its caused by straight RO or other factors. Thanks for bringing this tread up again.

[vendetta]

Low KH can led to a ph crash. KH is what buffers the ph.

I used in the past a combination of acid y regulator buffers by Seachem.. do you think I can use regulator buffer to grow the KH?.. or is it better and more easy with tap water?

[bs6749]

You can use baking soda to safely increase the KH of your water. Alternatively, if you find some rocks that contain limestone/calcium carbonate, you can put them into the tank and this will help raise your KH (buffering ability) but it will also tend to hold your pH around 8.0, which should be fine for your fish as I've kept discus, angelfish, rams, and other "soft water fishes" in these conditions and they thrived and spawned for me.