Some thoughts and opinions (these are not rules!)
No one laundry product works for everyone, Water composition is the major factor and different products work differently in different water conditions.
Some of the things on this page are controversial. Again - Karen's opinions are not rules. Do your own homework and make your own decisions.
Laundry products change over time and what I use also changes. BioKleen Laundry Powder is one that I have used for many years and it has always worked for me. I can find it locally and it is reliable for me. For a liquid, I (Karen), I don't have a favorite. It is difficult to find a liquid that doesn't have methylisothiazonlinone (MIT) in it. I don't like optical brighteners either. You can search online to learn about both of those ingredients. Read your labels. There does seem to be product quality variations batch to batch of laundry liquids, too. Unscented liquid from Tide is much too bubbly in my very soft water and a tiny bit of Tide oversuds for me, so I expect that it would be great in hard water. Generally, Tide cleans very well.
Regular Tide liquid is the most popular detergent for cloth diapers and it cleans well. It even works in cold water. However, increasingly more and more people cannot tolerate the smell of it. P&G changed it in recent years and the smell is more potent and doesn't wash out in rinse cycles anymore. The smell is designed to stay, called encapsulated fragrance. It takes a strong solvent to remove it, if it is even possible to remove the fragrance. The smell even transfers onto furniture. The smell doesn't go away for a long time after someone who used Tide or any fragranced petroleum-based laundry liquid sits down on a fabric couch. That concerns me.
Research the scary neurotoxic chemicals in fragrance for yourself and you'll switch all products to everything in your entire household too, especially if anyone in your home has ever had a migraine. The fragrance chemical decision is yours to make, but it does bear some research. Fragrance is not a "nothing". They are actually chemicals in the air that you breathe in and they act on the brain and can even be addictive. This applies to air scents and perfumes too. Do you homework on the fragrance issue, or just play it conservatively and choose something fragrance-free or at least unscented to keep it simple. Unfortunately laundry product manufacturers are not required to fully disclose ingredients on the label. Check ewg to org for ingredient information and fragrancefreecoalition dot com for links to pubmed and other studies about it.
There are two main categories of laundry products: Natural coconut-based laundry products or mainstream petroleum-based laundry products. The natural ones seem to wear out fabrics more quickly (in the powdered form). That doesn't make natural a bad choice, it's just something to be aware of in your decision making process. Natural is often preferred for many reasons over petroleum based detergents. It's up to you.
These days you can find natural, unscented laundry detergents in regular stores. This was not the case 5 years ago. "Natural" detergents are usually coconut-based such as Ecover Zero Powder, Country Save, BioKleen, Seventh Generation and many others. The coconut is the source of the surfactant. Ecos Free and Clear and Green Shield are some more examples of coconut-based detergents.
I do not put other popular super-strong "specialty for cloth diapers" products such as Rockin Green in this category. They are either much too strong for natural fibers or people are using it improperly, perhaps up-dosing which is using too much of it. And when you use too much, the pH gets too high and especially in the presence of very hot water, you ruin things. Oxygen bleaches are still bleaches and they wear things out quickly. They can work, but be careful with the amount used. (Exception: Rockin' Green Funk Rock Ammonia Bouncer is good for fixing ammonia issues). Also you do have to be careful with natural detergents because redepositing of dirt can be a problem. I think it takes a lot of rinsing in warm water and/or add vinegar to get the pH down. Very high pH detergents do seem to wear out the laundry faster than the petroleum-based mainstream products but everything has tradeoffs. Do not use CMC degreaser, either. For the same reasons, we also do not recommend homemade detergents. In my experience this type of product causes premature wear and fabric destruction, not to mention roughness and fading and redepositing of soil. Please don't destroy your cotton by overdosing your laundry with products specifically made for stinky microfiber. Cotton is biodegradable. It is not made of plastic or petroleum. It washes well for that reason, but in the end you can compost it. Separate your loads by fabric. When you wash cotton separately from microfiber, you will see that the cotton comes clean easily and it's the microfiber that is the problem. Microfiber really does need harsh cleaning so use strong products on them in a separate load, or replace microfiber with cotton inserts for washing convenience. Choose something mainstream (unscented) or suitable for cotton for your cotton. If you want to add sodium percarbonate to your laundry then do it separately by adding oxygen bleach (oxygen cleaner). Sodium percarbonate is a bleaching agent. I suspect that the overuse of this ingredient that might be causing the problems that we see with some specialty for cloth diapers products which contain high amounts of this bleaching agent. Microfiber is hard to clean. Stick with 100% cotton for easiest washing.
Most people are fine with mainstream products such as an Unscented Tide or Arm and Hammer Sensitive Skin or whatever you find in a store. Petroleum-based mainstream products work. It is just a choice to make . Generally, they clean very well. Those products are just fine on cotton. However dryer sheets are always a no-no (don't even own them!) and choose unscented products. Check the EWG website for detergent information. Search for EWG.org or Environmental Working Group.org.
Please note that if you switch back and forth between typical detergents (that contain petroleum, whiteners, brighteners and enzymes) and the natural so called clean-rinsing products, that can be problematical. Rashes have been reported with switching types, so run a few extra cycles and change promptly if you switch detergent category types to make sure everything is ok. I think it does take a few cycles to make the change-over from mainstream petroleum based to natural coconut-based detergents. Some people use both kinds back and forth and have no issues, but I mention it so you are aware to check for a potential issue. If switching from scented mainstream detergent, that can take a very long time to clear out of your laundry and your machines, for example. Clean your dispensers and wipe out the machine, too. It is quite difficult to clear out the perfume scents of the mainstream detergents from everything but it is worth the effort, I think.
Also, some people have mistaken the term "clean rinsing" by thinking that it somehow required less rinsing than another detergent. That's not right! All laundry products must be fully rinsed, and warm or hot water rinses so much better than cold for all laundry products. Clean rinsing means that when the diapers are fully rinsed, it does not leave a residue. When fully rinsed out and used full time, the clean rinsing products work well but are best-suited to neutral or acidic water.
If the pH of your water is high and you are using clean rinsing products containing soda ash, washing soda, sodium percarbonate, sodium peroxyhydrate and such, the diapers may end up too alkaline also and that can lead to red bottoms. Rinse the diapers well. Rinse with vinegar to bring down pH if your water is high pH or if you notice a red tinge to skin. Skin does prefer lower pH so adding vinegar to rinse water is helpful for many people. Don't overdo it and don't use it on covers. Be careful about voiding warranties when you decide to use vinegar but generally vinegar is helpful. It does not void our prefold or Workhorse warranty, but it could void the warranty on diaper covers, for example.
Consider occasionally adding a sanitizer to you diaper load. Common sanitizers are very diluted bleach or an additive-free oxygen cleaner or borax added to your hot cycle now and then with your detergent. Know this - all detergents are designed for cleaning, not disinfecting (unless it's a product with added disinfectant) so you also need to add a disinfectant to do the sanitizing. When you place an order from GMD and you add the booklet your cart you'll receive an 16 page "Green Mountain How-To Booklet" which explains all this more fully so you can make the detergent decision that is best for your laundry situation. The Booklet is a wealth of cloth diapering how-to information, available WITH an order. Add it to your cart from this link Free How-To Booklet link or check the box for it in on the Checkout page.
Detergent is your friend. It's needed. Skimping on how much detergent you use will not get things clean, but still you have to fully rinse so it's always a learning process at first to get your amounts right for your water conditions no matter what laundry products you choose.
Natural laundry products do seem to fade colors over time, which to be expected with a high pH products. I do keep trying different detergents (but hey, that is part of my job to try different detergents to learn about them). My family is sensitive to some mainstream detergents and to some "natural" detergents. If I try something new that is a problem, my husband catches me and asks, "did you try a different detergent?" He knows because his skin gets rashy. This can happen with babies, too. Start with what you know works for you already. Switch to the unscented version if you aren't using unscented yet. Hopefully, that will also work fine for baby. What will work in your water? I don't know. Water varies a lot. This is why so many different kinds of detergents and variations of them exist. Everyone likes different things and different products do work differently in different water and different washers, too.
NOTE: Just like oxygen cleaner and other powders don't dissolve well in cold water, neither does most natural laundry powders. In cold water, they clump and won't dissolve. Choose warm or hot water for powder. Warm water is much better for rinsing, too. Consider the liquid version of your natural detergent for cool water washing. The liquid is easier to use and seems to leave diapers softer than the powder versions do, I think.
Calgon or other water softeners are fine. Put them in the water before adding the detergent for best results. But they tend to have scents so since I really don't like my laundry to smell like perfume or flowers, I like unscented. Charlie's Soap Laundry Booster & Hard Water Treatment doesn't have a smell but it is very high pH so rinse it completely to get the pH back down. It uses a biodegradable phosphate (Potassium diphosphate) that leaves no residue on your clothes while softening your wash water. But it's not really for septic systems. Green Mountain Diapers does not sell Charlie's products nor do we have an affiliation with EWG nor with any laundry product mentioned. Charlie's Soap is a registered trademark of Shiloh Products, Inc and other products mentioned are owned by their trademark owners.