Having problems...my set up is as follows:

72 gallon bowfront tank, Pro clear wet/dry 125, prefilter by LifeReef, with a prefilter sponge, pump Mag500, 2-200watt watt heaters in sump set at 84 degrees.

Substrate.- . 60lbs (or 5 bags) of Fluorite AND 80lbs (or 4 bags) of Eco-Complete: mixed together, this gave me 2 ½ - 3 inches on front and 3 ½ - 4 inches on back of tank…

Lighting - Current PC with two daylights 65 watt (10K) and two daylights 65 watt (6500K)..and two moonlights…giving me a total of 262 watts or 3.6 watts per gallon. I have timers set up so two 65 watts are on 4 hrs a day, but all four 65 watts are on 12 hrs a day....

Plants - Cryptocoryne wendti (Crypts)i, Sagittaria subulata (Narrow Leaf Sag), Sagittaria subulata (Broad Leaf Sag), Rotala Indica andmacrandra (red plants, wanted some color), Sagittaria subulata (dwarf Sag), Glossostigma elatinoides (ground cover), Microsorum pteropus (java fern) , nymphaea stellata (dwarf lily), anubias nana and dwarf onion plants.

UV Sterilizer – 15w “Current Gamma Aquarium UV”, not hooked up yet

CO2 - still working on it...

I plan on adding, after I finish cycling the tank, 3-6 rummy nose tetras, 1-2 bristle nose cats, 2 german blue ram, 1 flying foxes, 1-2 otos, and maybe some corys. After I feel the tank is stable enough, I would like to add 6-8 discus…

I set the tank up on 9/12. That day, my ph was 6.0 (tap water). On 9/16 my readings were ph 8.0, GH 4.0, KH 9.0, c02 (by grid) 2.7, NH3 0, NO2 <.3 and Phosphates 0.. Ran to LFS and bought Seachems Acid Buffer..after adding 12 tsp over several days, I retested on 9/20 & 9/21 and readings were ph 7.2, GH 8.0, KH 3.0, c02 (by grid) 10.0, NH3 0, NO2 <.3 . My LFS also said I should use R/O-D/I water (of course buy it from him at 50 cents a gallon), so on 9/22 I did a 20 gallon water change using LFS R/O water (testing Ph was 5.5). On 9/26 I retested and my ph was back up to 8.0. I stopped my testing, and didn't open the R/O unit which I purchased from airwaterice which arrived today.

I have kept tropical fish for over 20 yrs, have had fish only salt water tanks and my reef tank has been set up for almost a year now..but I have NO experience with live plants OR co2. Will a co2 system added to my tank lower my ph from 8.0 to between 6.0 and 7.0? (I'm not planning on breeding the discus, I just wanna look at em...grrrrr). Should I use the R/O system also? I don't find a need for the R/O system for my reef tank, no major problems using my tap water for weekly water changes. I do use my drinking water R/O system for top offs, but the R/O system under my sink makes water at a snails pace, and if i find the need to do water changes on my discus tank 2-3 or even 4 times weekly, I would need to use the second R/O system i bought....

I've searched the web for months now on co2 systems and am still confused on co2 reactors and diffusors. I've printed off a few articles and am still not confident enough to put an inert gas canister under my tank. Any help anyone can give me I'd really appreciate..thanks all........

Your tap water is fine for your discus and you don't need to use the R/O water unless you are planning on breeding discus.

For now I would forget about the R/O water and read and study about CO2 systems.

The majority of algae problems are caused by lack of CO2, so you want to get it right from the beginning. I would make sure to read Tom's post on CO2 and all of the information here in general. This is the best place on the web for information on growing aquatic plants.


Bill

First off, there is no need what-so-ever for RO water in a planted tank. In fact, its counter productive IMO since you have to add all the nutrients back anyway. Especially considering you have reef tank doing well on your tap... this tells me your tap water is probably pretty good stuff. Personal opinion, send the unit back.

As for the pH issue. Adding CO2 will indeed lower your pH. How much depends on how fast you put it in, and how well you diffuse it. Look back at the pH/CO2 chart you referenced and using your kH of 9. I'd say you can safely lower your pH with CO2 to a bit under 7. As you add the CO2, the pH will drop, when it gets to about ~6.9 you'll have ~34ppm of CO2 (by my chart). This is a safe range. Adding more CO2 will continue to drop the pH, but you start risking your fish if you go to far.

As for how to diffuse the CO2 you introduce, there are many ways from air stones, to in-line reactors, to upside down bowls, blah blah blah. For a 72 gallon tank, my best recommendation is to read this article:
Venturi Design
Its the easiest/cheapest/most effecient way I've seen.

I don't know how good I am at clearly answering questions but I hope that helped. If not, ask again and I'll try to clarify. Regardless, I'm sure others will be chiming in with better answers than I.

Good luck,
Blake

Blake, u have answered my questions very clearly and really appreciate the input. I have been devouring all info on this site re:co2. I came across some articles/threads Tom wrote about a "diffsor stone"...simply hooking your co2 gas line to this http://www.aquaticeco.com/index.cfm/.../9775/cid/2339 I'm also thinking about purchasing the co2 regulator set from aquariumplanet http://aquariumplant.com/cgi-bin/cart/pr007.html AND the MILWAUKEE Automated pH/Co2 Controller http://aquariumplant.com/cgi-bin/cart/pr209.html . What do you think Blake? Tom? Thanks all....

Get a pinpoint pH meter, I hate those MILWAUKEE pH meters/controllers after seeing a number of issues with them from a several folks.

Measure your KH. Measure it and few times, and get an alkalinity test report from the tap water company.

Tell us what you found.

Regards,
Tom Barr

As for the Milwaukee regulater. Good stuff. I use one and have no problems with it. Make sure everything is snug... spend a couple days tweaking your flow rate to your needs and forget about it.

The air stone is questionable IMO. I use a stone type diffuser (not the same one as A-ECO has) and it barely keeps up with my 50 gallon's needs. That particular brand of stone may do a better job though. Heck, try it and let us know. Wish I had a more definate answer.

I agree with Tom about the pH controller but for a slightly different reason. I've never used one so I can't say they have issues. I simply don't think its worth the money. Save the money and buy the pH pen Tom is talking about. You have much more "stable" water than I (my kH is about 1 degree) and I use no controller and have had no problems with my plants or fish concerning pH swings. My pH does swing since I run the CO2 only during the day, but not enough to warrent trouble. Granted, I don't have fish that are as sensitive as discus.

Keep us updated.

Blake

Tom, I'm on well water...no water company to ask for a report...

Ok, tested my water today:
ph - 9.0
nh3 - 0
no2 - <.3
gh - 8.0
kh - 4.0 (tom, test 4 times in a row...got 4.0 each time...did you mean several tests all at once..or different days/times?)
phosphate - 0.0
c02 - .01 (my poor plants, which by the way, green ones are actually getting new growth, red ones are melting away....)
On well water, no alkalinity test....

Checked petplace, can get a pinpoint for 90$, so i'll scrap the milwalkee and purchase one of those along with the "top gun" regulator set. Will purchase the co2 tanks from Roberts Oxygen...Now for a diffusor???

Holding off on sending back the R/O unit....

Ok, so it was early.....TAP WATER TEST:

ph - 6.5
nh3 - 0
no2 - <.3
gh - 2.0
kh - 8.0 (test 3 times in a row...got 8.0 each time)
phosphate - 0.0
c02 - 77

So your KH and alkalinity are the same thing.
Your well water seems pretty darn good to me.

Regards,
Tom Barr